The People v. Pizarro ( 2013 )


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  • Filed 6/13/13 (unmodified version attached)
    CERTIFIED FOR PARTIAL PUBLICATION
    IN THE COURT OF APPEAL OF THE STATE OF CALIFORNIA
    FIFTH APPELLATE DISTRICT
    THE PEOPLE,
    F057722
    Plaintiff and Respondent,
    (Madera Super. Ct. No. M8517)
    v.
    MICHAEL ANTONIO PIZARRO,                              ORDER MODIFYING OPINION
    AND DENYING REHEARING
    Defendant and Appellant.                      [NO CHANGE IN JUDGMENT]
    THE COURT:
    It is ordered that the opinion filed herein on May 21, 2013, be modified in the
    following particulars:
    1.      On page 102, at the end of the partial paragraph ending “perpetrator‟s sample,” the
    following paragraphs are added:
    Based on this evidence, the trial court had no reason to find that
    Myers failed to follow correct scientific procedure. Accordingly, it did not
    abuse its discretion.
    4.      Our Concerns Related to Allelic Dropout
    We recognize that we are not a scientific body, but we are
    nevertheless concerned, as was defense counsel, that allelic dropout has the
    potential to falsely incriminate an innocent defendant, which is a serious
    legal concern, as we explain below.
    2.     The following sentence is added on page 102 as the first sentence of former
    part II.E.5.f.3.a. (now part II.E.5.f.4.a.), under the heading “The Theory,” to read as
    follows:
    The People cite Butler for the proposition that allelic dropout will
    not cause a problem if the same kit is used to test both the perpetrator‟s
    evidence sample and the defendant‟s reference sample.
    3.     The sentence in the first paragraph of former part II.E.5.f.3.a. (now
    part II.E.5.f.4.a.) on page 102, which presently reads as follows: “Butler and other
    authors propound the theory that allelic dropout is not an issue in criminal cases when the
    same primers (and PCR conditions) are used on both the perpetrator‟s evidence sample
    and the defendant‟s reference sample—as long as the two samples come from the same
    person.” shall now read as follows:
    Butler and other authors do propound the theory that allelic dropout is not
    an issue in criminal cases when the same primers (and PCR conditions) are
    used on both the perpetrator‟s evidence sample and the defendant‟s
    reference sample—as long as the two samples come from the same person
    4.     The first sentence of the second paragraph of former part II.E.5.f.3.a. (now
    part II.E.5.f.4.a.) on page 102, which presently reads as follows: “We begin with some
    statements of this theory.” shall now read as follows:
    We begin with some statements of this theory, including Butler‟s.
    5.     The last paragraph of former part II.E.5.f.3.d. (now part II.E.5.f.4.d.) on page 112,
    which presently reads as follows: “It is our hope in discussing these issues that the
    scientific community will reexamine the possible effects and management of allelic
    dropout in criminal cases and determine how best to safeguard the innocent while
    incriminating the guilty.” shall now read as follows:
    We recommend that the scientific community reexamine the
    possible effects and management of allelic dropout in criminal cases.
    6.     Former part II.E.5.f.3.e. on pages 112 through 115 is deleted in its entirety.
    2.
    There is no change in the judgment. Respondent‟s petition for rehearing is denied.
    _____________________
    Kane, Acting P.J.
    WE CONCUR:
    _____________________
    Poochigian, J.
    _____________________
    Franson, J.
    3.
    Filed 5/21/13 (reposted 5/23 to improve format of charts) (does not reflect 6/13/13 mods.)
    CERTIFIED FOR PARTIAL PUBLICATION*
    IN THE COURT OF APPEAL OF THE STATE OF CALIFORNIA
    FIFTH APPELLATE DISTRICT
    THE PEOPLE,
    F057722
    Plaintiff and Respondent,
    (Super. Ct. No. M8517)
    v.
    MICHAEL ANTONIO PIZARRO,                                                           OPINION
    Defendant and Appellant.
    APPEAL from a judgment of the Superior Court of Madera County. Edward P.
    Moffat II, Judge.
    Cliff Gardner, under appointment by the Court of Appeal, for Defendant and
    Appellant.
    Kamala D. Harris, Attorney General, Dane R. Gillette, Chief Assistant Attorney
    General, Michael P. Farrell, Assistant Attorney General, Stephen G. Herndon and
    Rachelle A. Newcomb, Deputy Attorneys General, for Plaintiff and Respondent.
    -ooOoo-
    *       Pursuant to California Rules of Court, rules 8.1105(b) and 8.1110, only the
    Introduction; Procedural Summary; Facts; the following parts of the Discussion: I., II.A.,
    II.E.1.a., II.E.1.e., II.E.1.f., II.E.2.a., II.E.2.f., heading of II.E.5., and II.E.5.f.; and the
    Disposition of this opinion are certified for publication.
    INTRODUCTION
    Tragically, in 1989, 13-year-old Amber Dawn Barfield was sexually assaulted and
    murdered. In 1990, defendant Michael Antonio Pizarro, Amber‟s older half-brother, was
    convicted of her first degree murder with special circumstances. In the first appeal in
    1992, this court reversed and remanded for a Kelly1 hearing regarding the DNA2
    evidence. On remand, the trial court ruled that the DNA testing was generally accepted
    within the scientific community and reinstated the conviction. In the second appeal in
    2003, this court found that the scientific evidence failed to satisfy the third prong of Kelly
    and reversed the judgment. In 2008, a second jury convicted defendant of first degree
    murder with a special circumstance finding. This is the third appeal in this case.
    Defendant again raises challenges to the DNA evidence, contends the trial judge erred in
    denying his motion for a new trial based on jury misconduct, and argues unanimity was
    required on the murder theory.
    After the second trial verdicts were received and the jury had been discharged, the
    parties and trial court learned that Juror No. 9 had read, during the trial, an earlier
    appellate opinion in this case.3 That opinion revealed several items of information that
    were not presented during the second trial, including: defendant had previously been
    convicted on all counts by another jury; defendant had been sentenced to life in prison
    without the possibility of parole; the appellate court‟s review of the evidence established
    that defendant had consumed beer throughout the afternoon and continued to drink at a
    1      People v. Kelly (1976) 
    17 Cal.3d 24
     (Kelly) (three-prong test must be satisfied
    before scientific evidence derived from new scientific procedures may be admitted).
    2      Deoxyribonucleic acid.
    3      The opinion Juror No. 9 read was actually an opinion issued in August 2002 that
    was later vacated after this court granted rehearing. It subsequently issued its opinion in
    2003 (People v. Pizarro (2003) 
    110 Cal.App.4th 530
     (Pizarro II), disapproved on other
    grounds in People v. Wilson (2006) 
    38 Cal.4th 1237
    , 1250-1251). There is no substantive
    difference between the two opinions as it relates to the jury misconduct issues.
    2.
    party; defendant testified at his first trial in which he contradicted portions of his
    statement to the police and admitted that “alcohol made him violent”; the Federal Bureau
    of Investigation (FBI) analysis presented at the first trial concluded that the DNA from
    the semen on the vaginal swabs matched the known blood sample of defendant; the case
    had been appealed twice; and the appellate court determined that the evidence against
    defendant was a “„strong circumstantial case‟” and that the DNA evidence clearly
    “„“sealed [his] fate.”‟” (Pizarro II, supra, 110 Cal.App.4th at pp. 553, 634.)
    During the second trial, the trial judge regularly admonished the jury not to
    consider anything other than the evidence presented in the courtroom. Juror No. 9
    repeatedly violated that instruction during the trial. The parties and the trial court agree
    that Juror No. 9 committed misconduct. They disagree whether that misconduct
    amounted to juror bias, warranting a new, and third, trial.
    We sympathize with the trial judge who, having presided over two jury trials and a
    prolonged Kelly hearing amid two appeals, was called upon to make the difficult decision
    of whether to grant yet another new trial in a case that was then almost 20 years old. The
    trial court ultimately denied defendant‟s new trial motion, finding it to be a “close case”
    and a “real hard, hard decision to make.” While we agree with the trial judge that the
    juror misconduct in this case amounted to “gross misconduct” and was “absolutely
    outrageous,” we disagree with his decision denying the new trial motion. We conclude
    that reversal is required. Despite the good efforts of the trial judge and the attorneys to
    conduct the trial in accordance with the rules of evidence, procedure, and substantive law,
    the juror‟s misconduct in disobeying the court‟s repeated admonitions and in
    investigating the case on his own made a mockery of the trial process and prejudiced
    defendant. We view that juror‟s behavior in this case as criminal.4
    4      Juror No. 9 arguably violated Penal Code section 96 (juror commits felony if he or
    she willfully and corruptly receives information except according to the regular course of
    proceedings) and could have been criminally prosecuted for his misconduct. (See In re
    3.
    We conclude that the extraneous material (the appellate opinion) read by Juror
    No. 9, judged objectively, is inherently and substantially likely to have influenced the
    juror, warranting a new trial. Accordingly, we reverse the conviction.
    We are mindful of the burdens—in terms of time, money and proof —of any
    prospective retrial of this case involving an awful crime that occurred 24 years ago. In
    this third appellate opinion on a case that has been twice tried, we take no satisfaction in
    the decision we unavoidably must render, in accord with our duty, as a consequence of a
    juror‟s outrageous misconduct that undermines the soundness of a verdict in our system
    of justice.
    Although we uphold the admission of the DNA evidence, we conclude that the
    widely held belief that allelic dropout cannot cause false results in a criminal case as long
    as the defendant‟s and the perpetrator‟s DNA samples are tested in a consistent manner is
    based on the improper assumption that the defendant is the perpetrator—in other words,
    that the defendant is guilty. We determine in this case, however, that any error was
    harmless.
    PROCEDURAL SUMMARY
    On August 11, 1989, the Madera County District Attorney charged defendant as
    follows: count one, first degree murder (Pen. Code, § 187) with the special
    Carpenter (1995) 
    9 Cal.4th 634
    , 673 (Mosk, J., dis. opn.) (Carpenter).) We believe a
    juror who so brazenly disregards and willfully violates the court‟s admonition not to
    investigate or consider matters outside the evidence received in the courtroom should be
    criminally prosecuted. Jurors take an oath to follow the court‟s instructions. When a
    juror knowingly disobeys a court order, he or she should be held accountable. We
    recommend that the Advisory Committees on Criminal Jury Instructions and Civil Jury
    Instructions include in their Pretrial Instructions a reference to Penal Code section 96 to
    impress upon jurors the seriousness of their task and the importance of obeying the
    court‟s instruction not to investigate the case or consider matters other than the evidence
    received in the courtroom. One wonders if Juror No. 9 would have committed this
    misconduct if he was told it could subject him to criminal prosecution.
    4.
    circumstances that the murder was committed while defendant was engaged in the crime
    of rape (Pen. Code, § 190.2, subd. (a)(17)) and while he was engaged in the crime of a
    lewd or lascivious act upon a child under age 14 (Pen. Code, § 190.2, subd. (a)(17));5
    count two, forcible lewd or lascivious act on a child under age 14 (Pen. Code, § 288,
    subd. (b)); and count three, forcible rape (Pen. Code, § 261, subd. (2)). Defendant pled
    not guilty.
    In 1990, a Kelly hearing was held to determine the admissibility of the results of
    DNA identification evidence. The trial court ruled the results were admissible.
    The jury found defendant guilty on all counts and found true the special
    circumstances. The trial court sentenced defendant to life in prison without the
    possibility of parole on count one, to be served consecutively to the upper term of
    eight years on count two. The sentence on count three was stayed pursuant to Penal Code
    section 654.
    On appeal, we remanded the case to the trial court for a full-blown Kelly hearing
    to determine the general scientific acceptance of the FBI‟s DNA profiling procedure and
    the FBI‟s Hispanic database. (People v. Pizarro (1992) 
    10 Cal.App.4th 57
    , 95-96
    (Pizarro I).) In March 1998, after a hearing conducted in 1994 and 1995, the trial court
    found the procedure and the database generally accepted and the evidence admissible.
    Defendant appealed. In 2002, we published an opinion reversing the judgment. We
    5       In 1989, Penal Code section 190.2, subdivision (a)(17) provided: “(a) The penalty
    for a defendant found guilty of murder in the first degree shall be death or confinement in
    state prison for a term of life without the possibility of parole in any case in which one or
    more of the following special circumstances has been charged and specially found under
    Section 190.4, to be true: [¶] … [¶] (17) The murder was committed while the defendant
    was engaged in or was an accomplice in the commission of … the following felonies: [¶]
    … [¶] (iii) Rape in violation of Section 261. [¶] … [¶] (v) The performance of a lewd or
    lascivious act upon [the] person of a child under the age of 14 in violation of
    Section 288….”
    5.
    granted rehearing, and then in 2003, we published a final opinion in Pizarro II, supra,
    
    110 Cal.App.4th 530
    , reversing the judgment.
    In 2008, a second jury found defendant guilty on count one, first degree murder
    with the special circumstance that the murder was committed while defendant was
    engaged in the crime of a lewd and lascivious act, but the jury found not true the special
    circumstance that the murder was committed while defendant was engaged in the crime
    of rape. The jury found defendant guilty on count two, forcible lewd or lascivious act on
    a child under age 14. On count three, the jury found defendant not guilty of rape, but
    guilty of the lesser included offense of statutory rape.
    Defendant unsuccessfully moved for a new trial. The trial court sentenced
    defendant to life without the possibility of parole on count one, a stayed eight-year term
    on count two, and a stayed three-year term on count three. Defendant appealed.
    FACTS
    On June 10, 1989,6 defendant and his wife, Sandy, both about 20 years old, and
    their five-month-old baby drove to North Fork from Clovis in their white Toyota pickup
    truck to visit defendant‟s mother, Chris Conston, and his sisters.7 Defendant and Sandy
    did not visit North Fork often; as far as Sandy knew, defendant had not been there in the
    several weeks prior to this visit, and the last time she had been there was in late 1988.8
    The drive to North Fork took about 45 minutes and they arrived at Chris‟s house around
    noon. Defendant‟s sisters, Gloria, Amber, and Angie, who still lived at home, were there,
    as well as Gloria‟s boyfriend, Billy, who was about 17 years old. After they visited for a
    6      All references to dates are to 1989 unless otherwise noted.
    7      Defendant and Sandy married in September 1987 and divorced in October 1997.
    8      Defendant worked at a lumber mill in Auberry, about 30 minutes from home in
    Clovis. If he was working on a Saturday, he would stay in Auberry after work on Friday
    and come home after work on Monday. Sandy did not remember his being gone from
    home during the week prior to June 10.
    6.
    while, everyone went to the elementary school to watch the men play basketball. Sandy
    knew defendant and other people were drinking because they were “just overly happy.”
    After the basketball, they returned to the house. During the remainder of the day,
    defendant left the house three times without Sandy. He did not tell Sandy where he was
    going, but she assumed he was going to the store. After his third trip, he told Sandy his
    friends were going to a party and he wanted to go. Sandy told him she wanted to go
    home, but they ended up going to the party at Shady Oak trailer park a few miles up
    Road 200, which was a two-lane mountain road with lots of trees, steep embankments,
    and no streetlights.
    When Sandy and defendant arrived at the party, Amber, Gloria, and Billy were
    already there. In total, there were about eight people at the party, one of whom was Scott
    Nelson. Sandy talked with Amber while defendant drank beer and hard liquor with his
    friends. Sandy did not drink much because she was nursing the baby. She may have had
    one-half of a beer. She was not happy to be there. She thought defendant seemed to be
    handling his alcohol “okay.” He was a regular drinker and she had seen him in various
    stages of intoxication in the previous couple of years.
    At about 10:00 or 10:30 p.m., Amber left the party with Billy and Gloria. Sandy
    asked defendant to leave, but he refused.
    At about 12:30 a.m., Sandy took the baby and left for home in the truck. She
    drove only a few minutes to Bass Fork Market, then decided she did not want to drive by
    herself, so she returned to the party. Defendant came outside and they argued for five or
    10 minutes about going home. Defendant went back inside for about 20 minutes and
    came back out around 1:00 a.m.
    Defendant was angry with Sandy and he started walking toward Road 200, which
    was about 100 feet away from the trailer. He told Sandy he was going to his mom‟s. He
    had been drinking, but he was not staggering, falling down, or slurring his words. Sandy
    got into the truck with the baby and followed defendant down the road toward North
    7.
    Fork. He was zigzagging across the road, walking from one side to the other and hiding
    behind trees and rocks. He appeared to be hiding from Sandy. At one point, he ran up an
    embankment on the side of the road, then back down to the road. Eventually, he started
    running on the road. He hit the hood of the truck and told Sandy not to stop in the middle
    of the road. As she followed him, she yelled at him to get in the car. She told him she
    just wanted to go home. Sandy had seen him intoxicated before, but she had never seen
    him act this way. This continued for more than 15 minutes, until Sandy gave up and
    drove into North Fork to Chris‟s house. She knocked on Chris‟s front door and
    eventually Amber opened the door. Sandy told her defendant was “out there” and she
    could not get him in the truck because he did not want to come. Amber said, “[W]ell,
    let‟s go get him.” Sandy told her to ask her mom. Amber left and returned with Chris,
    who gave Amber a turquoise flashlight and told them to be careful.
    Amber got in the truck and held the baby. Sandy drove back to the place she had
    last seen defendant. When they saw him walking, Sandy made a U-turn. They followed
    him and told him to get in the car, but he refused. He went up a hill and Sandy shined the
    flashlight on him. He came down and started running. Amber got out of the truck and
    set the baby on the seat, leaving the door slightly open. Sandy saw Amber in the
    headlights as she walked across the road toward defendant. Sandy picked up the baby
    and pulled the door closed. She followed Amber for about 10 seconds. After that,
    defendant and Amber disappeared. Sandy never saw Amber again.
    Sandy drove forward. She held her door open as she yelled for defendant and
    Amber because the driver‟s window was not operable. She heard nothing. It was dark
    and she could see nothing other than what her headlights illuminated. She yelled for
    defendant and Amber to turn on the flashlight, flash the light, or do something. Then she
    saw a flash of light behind a bush. The light pointed upward. Sandy closed her door,
    pulled forward, and made a U-turn. She stopped in front of the bush and yelled. She was
    holding the baby, so she could only yell from her open door, which was now on the
    8.
    opposite side of the truck from the bush. There was no response and no more light, so
    she pulled forward, made another U-turn, and returned to the spot where she had seen the
    flash of light. She parked, opened the door, and yelled for defendant and Amber. She
    heard “a scream, a muffled sound, and nothing else.” It was as if someone put a hand
    over a mouth. It scared her and “[f]reaked [her] out.” She closed her door and
    immediately drove back to Chris‟s house. She told Chris, “I don‟t know what happened.
    I heard a scream, a muffled sound. I‟m scared. I don‟t know what‟s going on.” Chris
    told her to come in and they called the sheriff‟s department. Deputy Loring was on duty
    that night and he received the call around 2:50 a.m.
    Sandy drove to Sierra Automotive at the intersection of Roads 200 and 222 to
    meet the deputies. Deputy Loring and Deputy Weisert arrived and met Sandy in the
    parking lot. Sandy was sitting in the white truck with the baby and she seemed upset and
    frightened. She told them what had happened and they began searching for defendant
    and Amber. Sandy‟s parents came from Fresno to take her home. Sandy left the white
    truck at Chris‟s house.
    Just before 6:00 a.m., defendant arrived back at Chris‟s house. At about 6:00 a.m.,
    defendant called Deputy Weisert at the station. According to Deputy Weisert, defendant
    did not seem intoxicated. He said his sister was missing. He explained that he got into
    an argument with Sandy. His sister came looking for him and he told her he did not want
    to talk about it. He took off up the hill with her flashlight. She yelled at him about the
    flashlight and he threw it down the hill. He did not go back down, but later woke up in
    the bushes and started walking home. As he did, “some cops came upon him and accused
    him of kidnapping his sister. And then … he basically ran home and was followed by the
    cops.” He did not describe these cops to Deputy Weisert. But she and Deputy Loring
    had been the only officers on duty that night, and after Deputy Loring left around
    4:00 a.m., Deputy Weisert was the only officer on duty. The next officer would not come
    on duty until 6:45 a.m. In Deputy Weisert‟s opinion, defendant was telling her a story
    9.
    that could not be true. She knew that no other officers were on duty in the area and that
    they would not have known about the case anyway.
    At about 8:00 a.m., Deputy Lidfors went to Chris‟s house to speak to defendant.
    He was asleep, so Deputy Lidfors asked Chris to wake him up. When they spoke,
    defendant did not seem intoxicated or hung over; nor did he smell of alcohol. Defendant
    looked as if he had just woken up from sleeping out in the brush. He was wearing the
    same clothes he had worn the previous night, a white tank top and black and grey
    Oakland Raiders shorts. He was dirty and there were “stickers, grass stuff sticking off of
    his shorts.” Defendant told Deputy Lidfors what had happened. When Deputy Lidfors
    asked defendant if he could give him a description of where he had last seen Amber,
    defendant directed him to a specific area on the side of Road 200.
    Relying on that information, at about 8:30 a.m., officers found Amber‟s body
    about 16 feet from the shoulder of Road 200.9 The area was a mixture of grass and
    weeds with a lot of dirt. The grass was trampled down. Amber was nude below the
    waist, except that she was still wearing short dark socks. Her blue panties were down
    around her right ankle. Much of her body was covered in foxtails. Her right sock had
    foxtails on the ball and toe portion, and a large amount of dirt caked onto the heel, as if it
    had been dug into the dirt. The other sock had foxtails and some dirt on it. A turquoise
    flashlight was near her right foot. Her tan T-shirt and bra were both pushed up over her
    breast. Her right cheek was bruised and marked. Blood was smeared along her stomach,
    down her inner left thigh, across her right thigh, and on her right wrist. Her hands were
    clutching a large amount of dirt, grass, and foxtails. Her pants and shoes were under
    some brush near her body.
    9       Earlier that morning, officers had not found Amber‟s body because Sandy
    mistakenly directed them to an area about one-tenth of a mile from the area she had seen
    the flashlight go on.
    10.
    Detective Kern found evidence of activity only in the area where Amber was lying
    and in an area of dirt slippage on the embankment between the roadway and Amber. He
    found no evidence of activity either behind the crime scene up to the six-stranded barbed
    wire fence or on the other side of the barbed wire fence. Other than the dirt slippage area,
    he found no evidence of any entry to or exit from the crime scene.
    Gary Cortner, a senior criminalist, and Richard Kinney, a latent fingerprint
    analyst, both from the Fresno lab of the California Department of Justice (DOJ), arrived
    to help Detective Kern process the crime scene.
    At about 10:00 or 10:30 a.m., Sergeant Gauthier spoke to defendant at the station.
    The knuckles of defendant‟s right hand were somewhat red and there were some very
    minor scratches on one of his shoulders.
    Around 1:30 p.m., Amber‟s body was removed from the scene and taken to the
    mortuary.
    At about 2:00 or 2:30 p.m., Sergeant Gauthier took defendant back to Chris‟s
    house. As they drove on Road 200, defendant pointed to the crime scene area as the last
    place he had seen Amber.
    Sandy returned to North Fork to talk to defendant at Chris‟s house. She noticed
    that one of his hands was bruised and swollen. Defendant often injured his hands at
    work, but she had not noticed this injury the previous day.
    At about 4:00 p.m., Dr. Dalgleish, a pathologist, performed the autopsy on
    Amber‟s body at the mortuary.10 He noted that the right side of Amber‟s face was
    bruised, most likely from blunt force trauma. In the middle of a prominent bruise below
    her eye was a small puncture wound, which might have been a source of external
    bleeding. These injuries were consistent with blunt force by a hand or a flashlight,
    although some of the injuries could have been caused by falling. She had bruising around
    10     Dr. Dalgleish testified as an expert in pathology.
    11.
    her mouth and nose. Amber also suffered an internal hemorrhage in the scalp on the right
    front of her head, but no fractures of the skull or injuries to the brain. This scalp
    hemorrhage was consistent with blunt force by a fist or a flashlight, and could have dazed
    or disoriented Amber. These injuries were less than one day old and were all inflicted
    before death, but they were not fatal.
    Amber‟s external genitalia showed no sign of injury. Her hymen was open,
    demonstrating some sort of sexual activity at some time prior to her death. It was
    impossible to determine when that had occurred. Her uninjured condition did not suggest
    that she had not been sexually assaulted, but only that any sexual assault was not
    aggressive enough to cause injuries.
    Internally, Amber‟s neck area showed petechial hemorrhages, consistent with
    asphyxia hypoxia. There was no evidence of strangulation and no foreign material
    blocking the airways. Her lungs also suffered petechial hemorrhages, which resulted in
    congestive edema.
    Dr. Dalgleish collected vaginal and rectal swabs and made slides from them. He
    allowed the swabs to dry for about two hours and 45 minutes, upright, separate from each
    other, and away from the body. He took blood samples from the large vein around the
    heart and put them in clean, sterile containers. He took scrapings from the dried blood
    smears on Amber‟s body and placed them in a plastic vial. The samples were placed in
    the victim sexual assault kit. Amber‟s blood tested negative for drugs and alcohol.
    Dr. Dalgleish determined that Amber‟s death was caused by suffocation leading to
    asphyxia hypoxia. He believed the bruising around her mouth indicated pressure, such as
    from a hand over her mouth and nose, that prevented air from entering her airways.
    Generally, suffocation requires about five minutes of complete oxygen deprivation to
    cause irreversible brain injury. This would require a steady application of pressure.
    12.
    Based on the state of rigor mortis, he estimated her death as occurring about 10 to
    14 hours before the autopsy.11
    On June 13, Detective Kern returned to Chris‟s house. He advised defendant of
    his Miranda12 rights and defendant agreed to speak to him. After taking defendant‟s
    statement, Detective Kern and defendant drove to the crime scene. Defendant pointed
    out a tree about 150 yards from the crime scene where he had tried to hide when Sandy
    first brought Amber back to talk to him. Then he stopped Detective Kern at the side of
    the road adjacent to the crime scene. He pointed exactly to the crime scene and said it
    was where he spoke to Amber. He said he entered the area through the dirt slippage area.
    Defendant explained that after he and Amber finished talking, she wanted the flashlight
    back. He threw it to her, then turned and ran in the opposite direction of the roadway.
    The route he indicated would have been right through the barbed wire fence, which he
    did not mention. This was an area Detective Kern had searched and found no evidence of
    activity. Detective Kern then drove defendant to the area he said he went to sleep in the
    brush. Defendant said he ran straight from the crime scene through an open field and
    over a hill. He next showed Detective Kern the specific area that he spent the night.
    Detective Kern got out and examined the ground for about 50 yards, but found no tracks
    in the dirt, on the embankment, or on the roadway. He went to the top of the hill and
    examined a large area, but found no evidence that anyone had been there recently.
    Defendant had no response; he seemed not to remember where he had been.
    11     The defense expert agreed Amber‟s cause of death was most probably suffocation
    due to manual obstruction of the mouth and nose, probably by a hand. It was not due to
    her face being pushed into the ground because there would have been marks around the
    mouth and nose that were not present.
    12     Miranda v. Arizona (1966) 
    384 U.S. 436
    .
    13.
    1989 Lab Analysis
    The physical evidence was immediately analyzed at the Fresno DOJ lab. (After
    analysis by the DOJ, described below, the vaginal swabs were sent to the FBI for
    Restriction Fragment Length Polymorphism (RFLP) DNA analysis. That DNA evidence
    was introduced in the first trial and discussed at length in Pizarro II (and the opinion read
    by Juror No. 9), but it was not mentioned in the second trial. The following testimony
    regarding what was done in 1989 was elicited at the second trial.)
    Delia Frausto-Heredia received the victim sexual assault kit on June 12.13 She
    examined the vaginal swab first, as was her practice. She examined only one of the four
    vaginal swabs, all of which were initially in an envelope together. She used good lab
    practices, including the use of gloves and sterile instruments, and she worked with this
    evidence only. The vaginal swab tested positive for the presumptive presence of sperm.
    Frausto-Heredia saved the remainder of the vaginal swab to ensure that the defense could
    reanalyze it.
    Frausto-Heredia determined from the blood samples that Amber was a type O, a
    non-secretor, and a two plus one plus for phosphoglucomutase (PGM). Defendant was a
    type B, a secretor, and a one plus one plus for PGM. The PGM result of the blood
    scrapings from Amber‟s leg was consistent with Amber‟s own blood sample.
    Stephen O‟Clair, a senior criminalist, determined that the sperm on the vaginal
    swab was type B and therefore defendant was included as a possible donor.14 About
    10 percent of the general population are type B, and about eight percent are both type B
    and a secretor. O‟Clair also used good lab practices and safeguards against
    contamination.
    13     Frausto-Heredia testified as an expert in serology.
    14     O‟Clair testified as an expert in ABO blood typing.
    14.
    On June 13, Cortner examined the slides from the victim sexual assault kit.15 He
    found about 20 to 25 sperm on a slide, along with some bacteria that were streaked with
    the sperm.
    When Cortner examined photographs of the bruises on Amber‟s face, he observed
    some parallel lines fairly close together and wondered what could have made that pattern.
    He noticed that the turquoise flashlight‟s button had lines running across it and the word
    “Eveready” in the center. Cortner made an impression of the flashlight‟s button in clay
    and determined that the button could have caused the mark.
    In Amber‟s pubic hair sample, Cortner found none of defendant‟s pubic hairs.
    Similarly, in defendant‟s pubic hair sample, he found none of Amber‟s pubic hairs. In
    about 50 percent of sexual assault cases, Cortner observed a lack of pubic hair transfer
    between victim and perpetrator.
    On June 19, seven days after she examined the vaginal swab, Frausto-Heredia
    examined defendant‟s underwear. The underwear and the vaginal swab were never on
    the lab bench at the same time, and the disposable work surface was changed between
    each piece of evidence. The underwear tested negative for semen. Amber‟s panties also
    tested negative.
    On June 22, Cortner examined defendant‟s shorts and found two foxtails on the
    outside and nine foxtails on the inside. Defendant‟s underwear contained eight foxtails
    on the outside, four in front and four in back.
    Kinney found no fingerprints on the flashlight.
    2004-2008 Lab Analysis
    Many years later, in preparation for the second trial, Steven Myers, a senior
    criminalist at the Richmond DOJ lab, reexamined the evidence using Short Tandem
    15     Cortner testified as an expert in criminalistics and general forensic analysis.
    15.
    Repeat (STR) DNA analysis.16 Myers determined that defendant‟s DNA profile matched
    the DNA profile of the sperm on the vaginal swab. Defendant was included as a possible
    sperm donor.17 The estimated frequency of the profile (shared by both defendant and the
    evidentiary sperm), or the chance that a randomly chosen person would have that profile,
    was approximately one in 3.9 quintillion African-Americans, one in 350 quadrillion
    Caucasians, and one in 4.2 quadrillion Hispanics.18 In other words, the frequency of the
    profile was exceedingly rare.
    Myers found that the DNA profile of the epithelial cells on the vaginal swab was
    consistent with Amber‟s profile. He also determined that the DNA profile of the blood
    smeared on Amber‟s body was consistent with her own profile.
    Myers tested blood from Scott Nelson, collected on June 22, 1997, and from
    Scott‟s father, collected on March 21, 2007. Their profiles did not match the sperm on
    the vaginal swab and they were excluded as sperm donors. Their profiles also did not
    match the blood on Amber‟s leg.
    Defense Evidence
    Sandy Panico
    Sandy testified that when she and defendant left the party, defendant seemed
    intoxicated. She had seen him that drunk before, but she had never seen him act the way
    he did that night.
    16     Myers testified as an expert in forensic DNA analysis and statistical DNA
    analysis.
    17    Myers found it implausible that an analyst had contaminated the vaginal swab with
    semen. He had never seen transfer of that amount of sperm by contact.
    18     One quadrillion is one followed by 15 zeros, and one quintillion is one followed
    by 18 zeros.
    16.
    Kathleen Christine Conston
    Chris testified that when Sandy came back to the house the second time at about
    2:00 a.m. with only the baby, she was hysterical, upset, and scared. Sandy said she could
    not find Amber, she was gone, and she had screamed. Chris made her come into the
    house. Chris called the police and then they left in separate vehicles. Sandy drove the
    white truck and Chris took her vehicle.
    Chris testified that defendant returned to her house just before 6:00 a.m. He had
    scratches that appeared to be from going through brush. He told Chris he had spoken to
    Amber and then he took off, and on his way home, a policeman accused him of
    kidnapping his sister. Defendant did not change his clothes because he had not brought
    any extra clothes. When he woke up, he had “the mother of all hangovers. In fact, he
    was still kind of drunk.” Later, when he found out Amber had been killed, he cried. He
    was devastated because he and Amber were “extra close.” The news “hit him pretty
    hard.” Defendant stayed in North Fork after Amber‟s death and continued to work. He
    was a pall bearer at Amber‟s funeral. Two weeks later, he was arrested at work.
    Chris thought Scott Nelson came to her house on June 11. He drove a white
    pickup truck.
    William Davis
    William Davis had lived in North Fork most of his life. In 1988, he saw defendant
    and Scott at a Halloween party. They were both dressed in deputies‟ uniforms. Scott was
    pulling a gun in and out of a holster.
    William testified that he was familiar with trails that led from the area of the crime
    scene back into North Fork.
    William agreed that he and defendant were “real good friends” and “[b]est
    buddies.” They had known each other since grade school and they hung out together a
    lot, but William would not lie for defendant.
    17.
    Betty Lyons
    Betty Lyons was driving on Road 200 at about 2:00 a.m. on June 11. She came
    upon a tan Datsun pickup truck parked off to the side of the road. The truck‟s doors were
    closed and she did not see anyone inside. At a later time, Betty saw the same tan truck
    parked in front of Chris‟s house during the daytime.
    Gena Fabris
    Gena Fabris was driving on Road 200 sometime between midnight and 2:00 a.m.
    She noticed a small white pickup truck, like a Toyota, parked on the side of the road. She
    slowed to about 40 miles per hour as she passed it. The truck‟s lights were off and the
    doors were closed. She did not see anyone. When she drove by again five to 15 minutes
    later, the truck was still there. She still did not see anyone.
    Guy Clements
    Guy Clements was delivering newspapers that morning on Road 200. At about
    3:00 a.m., he saw a small white pickup truck and a sheriff‟s vehicle near Sierra
    Automotive. The white truck had the body style of a 1970‟s Datsun. West of the crime
    scene, he saw a second pickup truck that looked like a 1984 Nissan.
    William (Billy) Bain
    Billy was with Gloria at Chris‟s house on June 10. He and defendant had a few
    beers during the day. They went to the party that night and drank some more. There was
    marijuana at the party, but Billy did not recall if defendant was smoking it. Scott was at
    the party and he was getting loud. He was a braggart who liked to drink. He always tried
    to arm-wrestle Billy every time they saw each other because Gloria was his old girlfriend.
    That was the reason Billy and Gloria left the party around 10:00 p.m. Billy remembered
    that Scott drove a small white Dodge truck. Billy never heard Scott confess to a crime.
    Gloria Bain
    Gloria testified that defendant had one beer at the school on June 10. At the party
    that night, there was drinking. It was a normal occurrence for this group of people to
    18.
    smoke marijuana, but she could not recall if they did that night. Scott kept asking to arm-
    wrestle, which was his normal behavior. When Scott came to Chris‟s house the next day,
    he parked his white Dodge truck in the driveway. Defendant‟s truck was also in the
    driveway.
    Sergeant Gauthier
    Sergeant Gauthier did not see any blood on defendant‟s hands, body, or clothes.
    He did not swab defendant‟s hands or take fingernail scrapings. He took the samples
    required for a possible sexual assault.
    Sherri Atkisson
    Sherri Atkisson met Scott in June 1997. One day, they were talking with some
    other people. Scott consumed two beers. He seemed depressed and he said some
    alarming things. He said, “I killed her, not her brother, Mike.” He said Mike did not do
    it. He did not mention the female‟s name. He said he was driving down the street and he
    passed her. She was in pajamas. He stopped, she ran into a field, and he chased her. He
    had to keep her quiet because she was going to reveal that they had been having sex.
    Another car was coming and he was trying to keep her quiet. Scott said she died, but he
    did not explain how. About a week after this conversation, Sherri heard that Scott had
    died.
    When this conversation occurred, Sherri did not know defendant, Chris, or any of
    their family members. She had since met defendant‟s family in the courthouse hallways.
    On cross-examination, Sherri explained that Scott had been to her home several
    times, but she did not know him very well. She agreed that she did not know if Scott had
    been drinking before he came to her house on that particular day. When Scott mentioned
    pajamas, he did not mention the clothes Amber was wearing when she died. Noel
    Bartley was present and able to hear everything Scott said. Sherri denied that the only
    thing Scott said was, “I should just choke you out, too,” and she denied that she and her
    friends later concluded Scott must have been referring to Amber.
    19.
    After Sherri heard Scott‟s statements, she contacted the Madera County District
    Attorney‟s office and reported that someone had admitted a murder to her. She requested
    a return call, but no one ever called her back. In 2007 and 2008, however, she refused to
    talk to state agents who asked to speak to her about Scott‟s alleged statement.
    DISCUSSION
    I.     MISCONDUCT OF JUROR NO. 9
    A.     Introduction
    This was an awful case on many levels: an abominable crime with complicated
    DNA evidence, two jury trials and a lengthy Kelly hearing in between. And if that did
    not present enough challenges, the second trial was fraught with allegations of jury
    misconduct committed by different jurors during the presentation of evidence and during
    jury deliberations. We need not discuss all of these allegations, because we find Juror
    No. 9‟s flagrant misconduct in reading this court‟s 2002 appellate opinion in this case
    sufficient to warrant reversal of the conviction.19
    B.     Juror No. 9’s Misconduct
    Juror No. 9 testified at the new trial motion hearing. He admitted that at the
    beginning of testimony in the trial, he went onto the Internet, researched the case and
    found a prior appellate opinion in this case. That opinion revealed: defendant had
    previously been convicted on all counts by another jury; he had been sentenced to life in
    prison without the possibility of parole; on the day of the killing he had consumed beer
    throughout the afternoon and continued to drink at a party; he testified at his first trial in
    which he contradicted portions of his statement to the police and admitted that “alcohol
    19     Juror No. 9 also committed misconduct when he discussed this case with two
    neighbors during the trial. He also failed to divulge his prior criminal conviction during
    voir dire. The trial judge dismissed and replaced another juror for improperly discussing
    sentencing matters during deliberations. There were also allegations that “bullying” of
    jurors occurred in the jury room.
    20.
    made him violent”; the FBI analysis presented at the first trial concluded that the DNA
    from the semen on the vaginal swabs matched the known blood sample of defendant; the
    case had been appealed twice; and the appellate court determined that the evidence
    against defendant was a “„strong circumstantial case‟” and that the DNA evidence clearly
    “„“sealed [his] fate.”‟” (Pizarro II, supra, 110 Cal.App.4th at pp. 553, 634.)
    In one part of his testimony at the hearing, Juror No. 9 said that he read the entire
    opinion a few times; in another part of his testimony, he said that he only skimmed
    portions of it; and in yet another part, he said he “soaked in” whatever he could
    understand of the opinion. Specifically, he explained that he conducted this Internet
    research two or three times. He “researched the case during the testimony phase of the
    trial. [H]e found the process of researching the case to be quite simple and detailed
    information of the case to be readily available through the Internet.” As the testimony
    began, “[he] was lost. And that was really [his] reasoning to try and find to know where
    [he] was within the case.” He “felt that [he] wanted to do what was right for
    [defendant‟s] case and understand what was going on within the case. So that was the
    reason why [he] had pulled up some information, which turned out to be the very thick
    PDF file [the prior appellate opinion], to understand how the series of events had
    happened.” He “just wanted to understand the timeline[ and] the series of events of the
    case so [he could] understand so [he could] be on top of stuff while [he was]
    listening .…” He first read a current newspaper article about the case explaining it was
    an early DNA case for California courts and it was back in court. Then he turned to the
    prior appellate opinion, which “was so thick that it took [him] a long time.” He did not
    pay much attention to the other items produced by his Internet search because the prior
    appellate opinion gave him the “information [he] needed to know what was going on.”
    He downloaded the prior appellate opinion and kept it on his computer for about three
    weeks. He explained:
    21.
    “[I]nitially, … I just wanted to see it and when I seen that it had
    the—the timeline … [h]ow the timeline played out then that helped me out
    a lot. So I read all the way through from start to finish and that kind of
    gave me an overview to stay caught up with what you guys, in my opinion,
    what you guys were saying. I‟m sure you guys were doing a good job, but I
    guess I‟m slow. [¶] … [¶] No, [I did not read through the entire
    document;] when I got to the DNA stuff and markers and the alleles and all
    that it didn‟t … make sense at that time.”
    He said he would refer back to the prior appellate opinion when questions arose in
    his mind and he would attempt to clarify them. He mostly wanted to clarify the timeline.
    He said, “[I]t was mostly just facts that I was sticking to.” When asked if he read the
    portion of the facts that explained defendant‟s testimony in the first trial, he answered,
    “Oh, okay, yeah. No, I read everything to where it started getting really technical, like
    the DNA, the extractions of DNA, and the markers. I didn‟t understand the theory and
    stuff like that. But, uh, yeah, I did read this.” In reference to defendant‟s testimony, he
    explained:
    “I was looking at everything. I was looking at what people were
    saying, who said what. I was looking at who was where. I mean, that‟s
    timelines, that‟s what a timeline is. Where everybody was at. What they
    were saying. Who was involved. I mean, that‟s—that‟s what I was—and
    when it stop[ped] talking about stuff like that, and then it start[ed] going
    into theories and DNA markers and everything that I didn‟t understand, I
    stopped.”
    He said he just skimmed the DNA and “pulled out whatever [he] could
    understand, but most of it” did not make sense to him. He did, however, learn that the
    FBI was involved in analyzing the DNA evidence.
    When asked again if he read the prior appellate opinion from beginning to end, he
    answered: “Oh, absolutely. I mean, what I could understand I soaked in.”
    The prior appellate opinion contained information that was not disclosed in the
    second trial. It was also highly prejudicial to defendant, as we explain in more detail later
    in this opinion. There can be little doubt that if, during jury selection, Juror No. 9
    disclosed he had read the prior appellate opinion in this case, he would have been
    22.
    immediately excused for cause. In our view, if this disclosure had been revealed to the
    court during the trial, and the defense thereafter moved the court to discharge him, the
    trial judge would likely have done so. Here, in contrast, the disclosure occurred after the
    verdict, where the controlling question was whether the juror was actually or inherently
    biased. (Carpenter, supra, 9 Cal.4th at p. 653.)
    The parties agree that Juror No. 9 committed misconduct in consulting an
    extraneous information source and that prejudice is presumed unless rebutted. Defendant
    argues that the record establishes both actual and inherent bias on the part of Juror No. 9.
    The People dispute that actual bias against defendant was shown. As to inherent bias,
    they both cite cases in support of their respective positions that the presumption of
    prejudice was or was not rebutted.
    Actual bias does not require a showing of prejudice before a verdict will be set
    aside, because a defendant is entitled to 12 unbiased jurors, not 11, regardless of whether
    an unbiased jury would have reached the same verdict. (Carpenter, supra, 9 Cal.4th at
    p. 654.) On the other hand, a finding of inherently likely bias carries a presumption of
    prejudice that may be rebutted by an affirmative evidentiary showing or by a reviewing
    court‟s examination of the entire record. (Id. at p. 657.) The presumption is imposed
    because Evidence Code section 1150 precludes a defendant from affirmatively proving
    that the jury‟s deliberations were improperly affected by the misconduct. Since actual
    prejudice cannot be proven, bias is established if the extraneous material, judged
    objectively, is inherently and substantially likely to have influenced the juror.
    (Carpenter, supra, at pp. 652-653.) We conclude that is what happened here.
    C.     Standard of Review
    Whether prejudice arose from jury misconduct is a mixed question of law and fact
    subject to an appellate court‟s independent determination. (People v. Nesler (1997) 
    16 Cal.4th 561
    , 582-583 (Nesler) [reviewing court independently determines whether juror
    was biased].) Courts have stressed the particular need for independent review of the trial
    23.
    court‟s reasons for denying a new trial motion in juror bias cases. This is because the
    reviewing court must protect the complaining party‟s right to a fully impartial jury as an
    “„“inseparable and inalienable part” of the [fundamental] right to jury trial [(U.S. Const.,
    amend. VI; Cal. Const., art. I, § 16)]. [Citations.]‟” (People v. Ault (2004) 
    33 Cal.4th 1250
    , 1262.)
    D.      The Seminal Case of Carpenter
    In Carpenter, the defendant was found guilty of rape and murder, and was
    sentenced to death. The trial court granted the defendant‟s habeas corpus petition based
    on juror misconduct in obtaining extraneous information about the defendant‟s
    convictions and death sentences in a related case. While the trial court stated that the
    evidence of guilt was “„overwhelming,‟” it concluded that the usual harmless error test
    did not apply. (Carpenter, supra, 9 Cal.4th at pp. 644-645.) The Supreme Court
    reversed without prejudice to the defendant‟s right to file a new petition based on the
    combined records of the habeas corpus proceeding and the underlying trial. (Id. at
    p. 660.) In a four-to-three opinion, a divided Supreme Court set forth a two-part test for
    determining bias in an extraneous source case.
    First, inherent bias is shown if the extraneous material, judged objectively, is
    inherently and substantially likely to have influenced the juror—in other words, had an
    “„“effect on the verdict or … deprived the complaining party of thorough consideration
    of his case .…”‟” (Carpenter, 
    supra,
     9 Cal.4th at p. 652, quoting from Hasson v. Ford
    Motor Co. (1982) 
    32 Cal.3d 388
    , 416 (Hasson)), or the vote of the juror was influenced
    by exposure to prejudicial matter relating to the defendant (Carpenter, 
    supra, at p. 651
    ,
    quoting from People v. Marshall (1990) 
    50 Cal.3d 907
    , 950-951 (Marshall)). This test is
    “analogous to the general standard for harmless-error analysis under California law.”
    (Carpenter, 
    supra, at p. 653
    .) Under that standard, trial court error is deemed harmless
    unless there is a reasonable probability that it affected the verdict. (People v. Watson
    (1956) 
    46 Cal.2d 818
    , 836 (Watson).)
    24.
    Second, if the misconduct and surrounding circumstances make it substantially
    likely that the juror was actually biased against the defendant, the judgment must be set
    aside no matter how convinced the court might be that an unbiased jury would have
    reached the same result. (Carpenter, supra, 9 Cal.4th at p. 654.)
    Respectfully, we find the Carpenter majority opinion confusing and in some
    respects contradictory of the very case authority it relies on in reaching its conclusion that
    harmless error analysis applies to a case of inherent juror bias. In applying the harmless
    error analysis, Carpenter announces a rule that arguably undermines the integrity of our
    jury system. (Nesler, supra, 16 Cal.4th at p. 578 [requirement that verdict must be based
    on evidence developed at trial goes to fundamental integrity of trial by jury].) We are not
    the first court to question the reasoning, language and conclusion of the Carpenter
    opinion. (See People v. Von Villas (1995) 
    36 Cal.App.4th 1425
    , 1445-1458 (Woods, J.,
    dis. opn.).) We will explain.
    After summarizing and approving prior case law concerning juror exposure to
    extraneous information—including Marshall, supra, 50 Cal.3d at pages 950 through 951
    and People v. Holloway (1990) 
    50 Cal.3d 1098
     (Holloway), disapproved on another point
    in People v. Stansbury (1995) 
    9 Cal.4th 824
    , 830, fn. 1—for the propositions that
    (1) harmless error analysis for ordinary trial error does not apply to inherent juror bias
    based on a juror‟s exposure to extraneous material, (2) consideration of actual prejudice
    is not warranted in such circumstances, and (3) the ultimate question of whether a juror‟s
    exposure to extraneous material constitutes reversible juror misconduct is judged by an
    objective standard, namely, whether, based on an examination of the extraneous material,
    the court concludes the material is inherently and substantially likely to have influenced
    the juror (Carpenter, 
    supra,
     9 Cal.4th at p. 651, citing and quoting from Marshall), the
    Carpenter majority then inexplicably concludes its analysis by stating—directly contrary
    to Marshall and Holloway—that inherent juror bias based on extraneous material is
    governed by the general standard for harmless error analysis. (Carpenter, 
    supra, at 25
    .
    p. 653.) Not only does the majority opinion not disapprove Marshall and Holloway, it
    cites both cases approvingly for the rule that standard harmless error analysis does not
    apply in an inherent bias case. Then, in an apparent turnaround, the Carpenter majority
    declares, citing Hasson, that the presumption of prejudice can be rebutted where there is
    overwhelming proof in support of the verdict. (Carpenter, 
    supra, at p. 654
    , citing
    Hasson, supra, 32 Cal.3d at p. 417.) In other words, under harmless error analysis, the
    misconduct can always be deemed harmless if the evidence of guilt is strong enough.
    We find this proposition deeply troubling on many levels: it fails to uphold the
    venerable and constitutional right to an impartial jury; it fails to recognize the difference
    between assessing prejudice from ordinary trial error and from jury misconduct that
    impugns the guarantee of an impartial jury; it conflicts with several Supreme Court cases
    that did not apply harmless error analysis in an inherent bias case; it validates trial
    outcomes even when a juror has flagrantly disregarded the rules of evidence and
    procedure that the parties and trial judge have endeavored scrupulously to follow
    throughout a trial; it significantly impairs the presumption of prejudice, which the law
    imposes for this kind of jury misconduct; it holds that the only adverse “influence” on a
    juror that matters is one that changes a juror‟s vote; it unduly expands the role of the
    reviewing court in derogation of the jury‟s role; and it treats inherent juror bias the same
    as the erroneous introduction of evidence in determining whether the judgment should be
    reversed. We discuss each of these points in turn.
    E.      Effects of Carpenter
    1.     Right to Impartial Jury
    The United States and California Constitutions guarantee the right to an impartial
    jury. (U.S. Const., 6th Amend. [“the accused shall enjoy the right to a speedy and public
    trial, by an impartial jury”; Cal. Const., art. I, § 16 [“Trial by jury is an inviolate right”];
    People v. Wheeler (1978) 
    22 Cal.3d 258
    , 265 [art. I, § 16 includes the right to have
    verdict rendered by impartial jurors], overruled in part by Johnson v. California (2005)
    26.
    
    545 U.S. 162
    , 165-173.) The integrity of any trial depends upon the impartiality of the
    judge and jury. A major objective of the jury selection process and the trial court‟s
    repeated admonition that jurors not discuss the case with others and not consider matters
    outside the evidence received in the courtroom is to select jurors who are and will remain
    impartial. Any deficiency that undermines a trial‟s integrity calls for reversal without
    consideration of actual prejudice. (Carpenter, supra, 9 Cal.4th at p. 651, quoting from
    Marshall, supra, 50 Cal.3d at p. 951.)
    2.      Harmless Error Analysis
    Harmless error analysis presupposes an impartial judge and jury. (Rose v. Clark
    (1986) 
    478 U.S. 570
    , 576-579.) Our California Constitution specifies that no judgment
    may be set aside based on errors of misdirection of the jury, improper admission or
    rejection of evidence, errors of pleading, or errors of procedure unless the error results in
    a miscarriage of justice. (Cal. Const., art. VI, § 13.) Whether a miscarriage of justice
    occurs depends on whether the error affected the outcome of the case. (People v.
    Breverman (1998) 
    19 Cal.4th 142
    , 165.) When one of these enumerated trial errors is
    established, the harmless error test permits a reviewing court to consider the weight and
    strength of the evidence to determine if the lower court error was prejudicial, that is,
    whether the error affected the outcome. (Watson, supra, 46 Cal.2d at p. 836.) Juror
    misconduct is not one of the trial errors enumerated in article VI, section 13.
    Some lower court errors defy harmless error analysis, such as when a defendant is
    deprived of his right to counsel or where the trial judge is not impartial. (Arizona v.
    Fulminante (1991) 
    499 U.S. 279
    , 309-310.) The reason is this: “Each of these
    constitutional deprivations is a similar structural defect affecting the framework within
    which the trial proceeds, rather than simply an error in the trial process itself. „Without
    these basic protections, a criminal trial cannot reliably serve its function as a vehicle for
    determination of guilt or innocence, and no criminal punishment may be regarded as
    fundamentally fair.‟ (Rose v. Clark, 
    [supra],
     
    478 U.S., at 577-578
     (citation omitted).”
    27.
    (Id. at p. 310.) Likewise, an inherently biased juror who has received extraneous
    information prejudicial to the defense commits more than a simple error in the trial
    process. The misconduct infects the legitimacy of the entire trial framework.
    We believe the Marshall and Holloway decisions got it right in declaring that
    when it is inherently likely that extraneous information influenced a juror, an appellate
    court‟s opinion of the strength of the evidence of guilt should not and may not be used to
    uphold the verdict.20 If the extraneous information is sufficient to lead a reviewing court
    to conclude the information is substantially likely to have influenced the juror, that
    should end the inquiry. Inherent juror bias is still bias. The strength of the evidence can
    never erase a verdict‟s taint of juror bias, whether actual or inherent.
    Our case is analogous to cases where the jury has been misinstructed on the
    burden of proof. When a jury is instructed on a lower standard of proof than proof
    beyond a reasonable doubt, the harmless error test does not apply:
    “[I]f a reviewing court were to rely on its view of the overwhelming
    weight of the prosecution‟s evidence to declare there was no reasonable
    possibility that the jury based its verdict on a standard of proof less than
    beyond a reasonable doubt, the court would be in the position of expressing
    its own idea „of what a reasonable jury would have done. And when [a
    court] does that, “the wrong entity judge[s] the defendant guilty.”
    [Citations.]‟” (People v. Aranda (2012) 
    55 Cal.4th 342
    , 368 (Aranda),
    quoting from Sullivan v. Louisiana (1993) 
    508 U.S. 275
    , 281 (Sullivan).)
    Here, it is likely that Juror No. 9‟s receipt of the extraneous information contained
    in the prior appellate opinion prejudiced the defense, as we discuss below. It can never
    be proven whether Juror No. 9‟s exposure to the prior appellate opinion actually affected
    20      This is also in line with the American Bar Association standards (Marshall, supra,
    50 Cal.3d at pp. 950-951) and consistent with two earlier Supreme Court opinions that
    reversed convictions due to juror receipt of extraneous information, without giving any
    consideration to the strength of the evidence of guilt (People v. Honeycutt (1977) 
    20 Cal.3d 150
    , 157-158; People v. Pierce (1979) 
    24 Cal.3d 199
    , 206-207 [Watson harmless
    error test not appropriate]).
    28.
    his vote on the verdict. (Evid. Code, § 1150 [effect of a statement or conduct on juror‟s
    mental processes or voting is inadmissible].) But viewing the prior appellate opinion
    objectively, we conclude there is a substantial likelihood that the material influenced
    Juror No. 9 in a way that favored the prosecution and disfavored the defense. For
    example, the extraneous information may have, in Juror No. 9‟s mind, lowered the
    prosecution‟s burden, shifted the burden of proof to the defense, or made him skeptical of
    defense theories or evidence. (People v. Martinez (1978) 
    82 Cal.App.3d 1
    , 21-22; People
    v. Cumpian (1991) 
    1 Cal.App.4th 307
    , 312 [prosecutor‟s burden lightened or defense
    contradicted].) This is so even though Juror No. 9 may still have voted for guilt had he
    not received the extraneous information (as speculative as that is).
    The People, relying on Carpenter, contend that regardless of the quantity or
    prejudicial content of the extraneous information, and as long as it does not amount to
    actual bias, inherent juror bias should be deemed harmless if the appellate court
    determines the evidence of guilt is sufficiently compelling. But a defendant‟s right to an
    impartial jury is trivialized if a reviewing court can excuse serious jury misconduct by
    declaring that any reasonable juror who had not been exposed to the extraneous
    information would have found the defendant guilty anyway.
    3.     Conflicts with Precedent
    In 1990, just five years before Carpenter was handed down, the California
    Supreme Court decided Marshall and Holloway. Both opinions made the emphatic point
    that assessing prejudice resulting from a juror‟s exposure to extraneous information is
    “different from” and “less tolerant than” harmless error analysis for ordinary trial error.
    (Marshall, supra, 50 Cal.3d at p. 951; Holloway, supra, 50 Cal.3d at p. 1110.)
    Marshall‟s opinion was unanimous and Holloway included a single, concurring opinion
    and no dissent. Carpenter cites both cases approvingly and even quotes the above
    language in its own opinion. (Carpenter, 
    supra,
     9 Cal.4th at p. 651.)
    29.
    Marshall did not announce a new rule. Earlier Supreme Court decisions reversed
    convictions based on a juror‟s obtaining extraneous information without any discussion
    of the strength of the evidence or the harmless error rule. (See People v. Von Villas,
    supra, 36 Cal.App.4th at pp. 1446-1447 (Woods, J., dis. opn.).) And, lest there be a
    concern that the presumption of prejudice is too difficult to overcome in the absence of
    the harmless error rule, we point out that our Supreme Court has affirmed several cases
    since Carpenter, 
    supra,
     
    9 Cal.4th 634
     by finding that the information was not prejudicial
    to the defendant for reasons unrelated to the strength of the evidence of guilt. (People v.
    Thomas (2012) 
    53 Cal.4th 771
    , 819 [juror learning of witness‟s wife‟s recent shooting
    death not likely prejudicial because witness‟s testimony only involved defendant‟s
    purchase of a truck, which was not actively contested]; People v. Tafoya (2007) 
    42 Cal.4th 147
    , 195 [no likelihood of detrimental influence because the misconduct occurred
    after the verdict]; People v. Yeoman (2003) 
    31 Cal.4th 93
    , 159-160 [juror‟s improper
    remarks about drug screening procedures at jail not objectively prejudicial because
    whether the defendant was under the influence had little relevance to his mental state and
    whether he ever used drugs was not at issue]; People v. Jenkins (2000) 
    22 Cal.4th 900
    ,
    1048 [prejudice rebutted where juror who received information about case from news
    source was questioned during trial and trial judge made findings that juror learned very
    little, asserted he could be fair, was conscientious juror, and was relieved to learn that
    news account was false].)
    The Marshall test for evaluating prejudice in an inherent bias case is reasonable.
    If the reviewing court, after a careful review of the record, determines it is inherently and
    substantially likely that the extraneous material influenced the juror to the defendant‟s
    detriment, the judgment must be set aside. Prejudice in this context does not require
    proof of “actual prejudice,” that is, proof that the extraneous material changed a juror‟s
    vote. Thus, this prejudicial analysis is different from and less tolerant than harmless error
    analysis. (Marshall, supra, 50 Cal.3d at p. 951; Holloway, supra, 50 Cal.3d at p. 1110;
    30.
    Carpenter, 
    supra,
     9 Cal.4th at p. 651.) We would clarify the test by making explicit that
    influencing a juror to the defendant‟s detriment means likely to cause a juror to lower the
    prosecutor‟s burden, shift the burden to the defense, become skeptical of defense
    evidence or theories, deprive the defendant of thorough consideration of his case, or vote
    differently than the juror would have if not exposed to the extraneous information.
    4.      Disregard of Rules of Evidence and Procedure
    The Carpenter rule can lead to affirming verdicts in cases where the rules of
    evidence and procedure, which trial judges and counsel endeavor scrupulously to follow,
    are flagrantly disregarded by a juror or jurors. (Holloway, supra, 50 Cal.3d at p. 1110
    [court‟s and counsel‟s “efforts were to no avail”].)
    A jury trial is not a free-for-all presentation of evidence and argument. Guided by
    the rules of evidence, along with considerations of procedural and substantive law, a trial
    judge makes numerous rulings that regulate the admissibility of evidence. These rulings
    directly influence the parties‟ trial strategies, including what witnesses to call, what
    questions to ask and how to argue their cases before the jury. Counsel are bound by the
    trial court‟s rulings and are often expressly prohibited from bringing certain matters
    before the jury by way of evidence or argument. When jurors receive information about
    the case outside of the courtroom, all of the work of the court and parties to comply with
    the law is potentially undone. When the extraneous information is viewed objectively
    and the court determines the information is likely to have biased the juror against the
    defendant, it is not reasonable, in light of the trial court‟s efforts to limit the evidence to
    what is permitted by law, to uphold the verdict simply because a reviewing court thinks
    the defendant would have been convicted anyway.
    By way of illustration, assume a defendant is charged with robbery and there is
    overwhelming evidence of his guilt. Assume six jurors independently learn from reading
    the newspaper the following additional information that was expressly ruled inadmissible
    before the trial began: the defendant had four prior robbery convictions, had been to
    31.
    prison, was on parole when the instant offense occurred, confessed to the crime (a
    Miranda violation made it inadmissible), and had two other pending robbery cases. The
    six jurors do not share this information with any other jurors. No actual bias is shown.
    Can this serious misconduct be regarded as harmless and the verdict upheld simply
    because the reviewing court concludes that the defendant, in the absence of the jury
    misconduct, would have been convicted anyway? According to Carpenter, the answer is
    yes.
    5.     Presumption of Prejudice
    Carpenter renders the presumption of prejudice useless when the evidence of guilt
    is “„overwhelming.‟” (Carpenter, supra, 9 Cal.4th at p. 655.) A verdict should not stand
    if an objective view of the extraneous information leads to the conclusion that the
    extraneous information was substantially likely to have influenced the juror. (Marshall,
    supra, 50 Cal.3d at pp. 650-651.) Extraneous material can influence a juror in different
    ways: lowering the prosecutor‟s burden, shifting the burden to the defense, making the
    juror skeptical of defense evidence or theories, depriving the complaining party of
    thorough consideration of his case, or actually causing the juror to vote differently than
    the juror would have if he or she had not received the outside material. Since a defendant
    cannot elicit from a juror how the information affected the juror‟s thinking (Evid. Code,
    § 1150), the law imposes a presumption of prejudice to compensate for this evidentiary
    handicap. (Carpenter, 
    supra,
     9 Cal.4th at p. 652.) But allowing the weight of the
    evidence—as judged by a reviewing court—to overcome the presumption renders the
    presumption illusory. It is circular reasoning to impose the presumption because of a
    defendant‟s legal inability to prove actual prejudice, and then allow the prosecution to
    overcome the presumption by convincing the court that the defendant would have been
    convicted in the absence of the misconduct, when it is clear that the defendant cannot
    offer any rebuttal because he is precluded from asking jurors about the effect the outside
    material had on their thought processes.
    32.
    In other words, if the evidence is strong enough, there really is no presumption of
    prejudice, which means the only way a defendant will be entitled to a new trial based on
    jury misconduct in receiving extraneous information is to prove actual prejudice, which
    Evidence Code section 1150 precludes him from proving.
    6.     Influencing a Juror
    Although Carpenter does not say so expressly, one effect of applying the harmless
    error analysis in these circumstances is to declare categorically that the only influence on
    a juror that is relevant is whether the extraneous material actually affected the juror‟s
    vote. Carpenter ignores other inimical influences that may occur, such as lowering the
    prosecutor‟s burden, shifting the burden to the defense, or making the juror skeptical or
    distrustful of defense evidence or theories. It also ignores language in its own opinion
    that the presumption of prejudice is an “„“aid to those parties who are able to establish
    serious misconduct of a type likely to have had an effect on the verdict or which deprived
    the complaining party of thorough consideration of his case .…”‟” (Carpenter, 
    supra,
     9
    Cal.4th at p. 652, quoting from Hasson, supra, 32 Cal.3d at p. 416, italics added.) No
    one could reasonably argue that such influences are innocuous or do not matter. They
    can affect a juror‟s ability to cast his or her vote based solely on the evidence received in
    court and affect a juror‟s ability to hold the prosecution to the burden of proving guilt
    beyond a reasonable doubt.
    Thus, prejudice can be shown not only when the misconduct results in a different
    verdict, but also when the misconduct deprives the defendant of thorough consideration
    of his case. If an objective appraisal of the extraneous information leads a reviewing
    court to conclude that it is likely such information would lower the prosecution‟s burden,
    shift the burden to the defense, or create skepticism about the defense in the mind of a
    juror receiving such information, then the defendant has been prejudiced because he has
    been deprived of thorough consideration of his case by an unbiased jury.
    33.
    We know that if a trial court errs in instructing on the prosecution‟s burden of
    proof, the error is reversible per se; harmless error analysis does not apply. (Aranda,
    supra, 55 Cal.4th at p. 367; Sullivan, 
    supra,
     508 U.S. at p. 281.) We fail to discern a
    difference between a case where the trial court has misinstructed on the prosecution‟s
    burden of proof and a case of jury misconduct based on receipt of extraneous information
    that influenced the juror by lowering the prosecutor‟s burden of proof or shifting it to the
    defense. If the reviewing court believes the material was substantially likely to have
    influenced the juror in one of these ways, there should be no further opportunity to rescue
    the verdict under the harmless error test. This is particularly so when the misconduct is
    discovered after the verdict because there is no opportunity for the court to take
    corrective steps through admonition or other measures. (Holloway, supra, 50 Cal.3d at
    pp. 1111-1112.) The inherent bias test, as described in Marshall and Holloway, is
    reasonable, understandable and sufficient to identify reversible prejudice. The harmless
    error test should not be tacked on to it.
    7.      Expanding Reviewing Court’s Role
    Another concern is that Carpenter expands an appellate court‟s traditional limited
    role to one that includes weighing evidence to determine whether a jury would have
    convicted defendant absent the misconduct. While appellate courts are called upon to
    consider the weight of the evidence in applying harmless error analysis to ordinary trial
    error scenarios (Watson, supra, 
    46 Cal.2d 818
    ) and to cases in which federal
    constitutional error has occurred (Chapman v. California (1967) 
    386 U.S. 18
    ), such is not
    the case where the error is “structural” (Arizona v. Fulminante, 
    supra,
     499 U.S. at p. 309)
    or undermines the integrity of a trial (Marshall, supra, 50 Cal.3d at p. 951). A conviction
    marred by juror bias—actual or inherent—undermines the integrity of a trial. When a
    reviewing court nonetheless affirms a conviction by applying the harmless error test, then
    “„“the wrong entity judge[s] the defendant guilty”‟” (Aranda, supra, 55 Cal.4th at p. 368,
    34.
    quoting from Sullivan, 
    supra,
     508 U.S. at p. 281), and it oversteps its role as a reviewing
    court and treads on the exclusive domain of the jury.
    8.       Treating Inherent Juror Bias the Same as Erroneous
    Introduction of Evidence at Trial
    Carpenter declares that “a finding of „inherently‟ likely bias is required when, but
    only when, the extraneous information was so prejudicial in context that its erroneous
    introduction in the trial itself would have warranted reversal of the judgment.”
    (Carpenter, 
    supra,
     9 Cal.4th at p. 653.) However, these two situations (inherent juror
    bias and erroneous introduction of evidence) should not be treated the same.
    It is a common, everyday trial experience to have prejudicial evidence (or
    argument) introduced in open court after which the trial judge is asked to strike the matter
    and instruct the jury to disregard it. There is a standard jury instruction that reminds
    jurors not to consider matters that the court previously told them to disregard.
    (CALCRIM No. 104; CACI No. 106.) In most situations, any prejudicial effect is
    eliminated or at least mitigated by the court‟s instruction, since jurors are presumed to
    follow the court‟s instructions. (People v. Boyette (2002) 
    29 Cal.4th 381
    , 436.) Even if
    no corrective instruction is given, the attorneys have the opportunity to respond to such
    evidence with cross-examination, rebuttal witnesses and closing argument. Not so with
    inherent juror bias that is discovered after the verdict.
    Another difference is that jury misconduct based on receipt of extraneous material
    carries with it a presumption of prejudice, while the erroneous introduction of evidence in
    the trial itself does not.
    Finally, and most importantly, if inherent juror bias exists, then the parties have
    lost their constitutional right to have their case decided by an impartial jury. On the other
    hand, the introduction of erroneous evidence normally does not jeopardize a fundamental,
    constitutional right.
    35.
    F.     Confusing References in Carpenter
    The Carpenter majority confusingly cites Marshall for the proposition that in an
    actual bias case, harmless error analysis does not apply. (Carpenter, supra, 9 Cal.4th at
    p. 654, citing and quoting from Marshall, supra, 50 Cal.3d at p. 951.) We agree that the
    harmless error test does not apply in an actual bias case, but Marshall was not an actual
    bias case and never addressed the subject of actual bias. It dealt with inherent juror bias.
    Thus, the portion of the Marshall opinion that Carpenter cites in support of its
    declaration that harmless error analysis does not apply to actual juror bias was actually a
    statement the Marshall court made regarding inherent juror bias.
    The Carpenter majority cites Hasson as an example of the application of the
    harmless error analysis in an extraneous information case (Carpenter, supra, 9 Cal.4th at
    p. 654). But the portion of the Hasson opinion cited by Carpenter dealt with misconduct
    based on juror inattentiveness, not on a juror‟s receipt of extraneous information.
    (Hasson, supra, 32 Cal.3d at p. 414.) The Carpenter majority‟s characterization of
    Hasson as an example of a case in which the harmless error standard was applied in an
    extraneous information case is simply incorrect.
    G.     Reconsideration of Carpenter
    We respectfully urge our Supreme Court to reconsider its Carpenter opinion and
    to follow the Marshall-Holloway line of authority that excludes application of the
    harmless error analysis in an inherent juror bias case based on receipt of extraneous
    information. We believe that harmless error analysis should not apply to cases of juror
    bias, whether actual bias or inherent bias. The test of whether a juror was influenced by
    the extraneous information should not be limited to the situation where it caused the juror
    to cast a different vote than the juror would have cast if the extraneous material had not
    been considered. It should be sufficient to show juror bias if the extraneous material is
    substantially likely to have caused the juror to lower the prosecutor‟s burden, shift the
    36.
    burden to the defense, become skeptical of defense evidence or theories, or deprive the
    defendant of thorough consideration of his case.
    H.     Analysis of the Present Case
    1.      No Actual Bias
    Here, the trial judge determined that there was no actual bias on the part of Juror
    No. 9. We agree that the record does not support any finding of actual bias. Although
    his misconduct was flagrant, Juror No. 9 did not discuss what he did or what he learned
    with the other jurors and there is no indication that he prejudged the case. (Carpenter,
    
    supra,
     9 Cal.4th at p. 657 [“a biased juror would likely have told other jurors what she
    had learned”].) The trial court did not abuse its discretion when it ruled that Juror No. 9
    had no actual bias.
    2.      Inherent Bias and Prejudice
    The trial judge found, and both sides agree, that Juror No. 9‟s misconduct
    constituted inherent bias, which creates a presumption of prejudice that is rebuttable by
    the People or by the court‟s review of the entire record. We have considered the People‟s
    arguments and authorities and we have reviewed the record. In our view, the
    presumption of prejudice has not been overcome. We reach this conclusion under both
    the Marshall-Holloway test (objective standard applies to determine whether extraneous
    material is inherently and substantially likely to have influenced the juror without
    consideration of harmless error analysis or actual prejudice) and the Carpenter test
    (harmless error test does apply). We conclude that the extraneous information was so
    prejudicial in context that its erroneous introduction in the trial itself would have
    warranted reversal of the judgment. (Carpenter, supra, 9 Cal.4th at p. 653.)
    The People, however, assert that the presumption of prejudice has been overcome
    “since most of the additional information [J]uror [No.] 9 learned from this Court‟s prior
    appellate opinion—„a time line of the case, facts … and details about DNA‟—was
    37.
    presented to the jury anyway” and because the evidence was “truly overwhelming.” We
    address and reject both contentions.
    3.     The People’s Contentions Lack Merit
    a.      The Extraneous Information Was Not Introduced in the
    Second Trial
    First, the People contend that the juror misconduct does not require reversal
    because most of the extraneous information “was presented to the jury anyway.” In order
    to assess this assertion we will now juxtapose the contents of the prior appellate opinion
    with the evidence received in the second trial to determine whether inherent prejudice
    should be presumed or whether the People are correct that most of the extraneous
    information “was presented to the jury anyway.”21
    The second jury was not directly informed that there had been a first trial, that
    defendant had previously been convicted of the crimes for which he was then on trial, or
    that he had been sentenced to life in prison.22 The prior appellate opinion begins by
    stating that defendant was previously convicted of murder, forcible lewd or lascivious
    conduct on a child under age 14, and forcible rape. This information was potentially
    prejudicial to the defense because Juror No. 9 became aware that 12 other jurors had
    concluded unanimously and beyond a reasonable doubt that defendant committed these
    crimes. Moreover, the court and parties endeavored not to mention these matters to the
    second jury. This has some similarity to Holloway, where the court reversed a conviction
    based on a juror‟s misconduct in reading a newspaper account that revealed the defendant
    21      The trial judge commented, “And certainly, you know, [Juror No. 9 was] privy to
    a lot of information that he should not have been privy to.”
    22       For the most part, the attorneys and witnesses avoided mentioning that there had
    been an earlier trial. Instead, when necessary to refer to testimony given in the first trial,
    they characterized the first trial as a “previous proceeding,” “prior proceeding,” “earlier
    proceedings,” and the like, although one witness referred to “the original trial” and the
    “first trial.”
    38.
    was on parole for another assault when he was arrested for the charged crimes. The court
    explained:
    “The entire case was tried on the premise that defendant‟s prior
    record was inadmissible. There was no voir dire about it, no limiting
    instructions were given, and the parties went to great effort to excise such
    references from defendant‟s extrajudicial statements. The court had no
    chance to take any curative measures because of Juror Beck‟s concealment
    of the misconduct. In such circumstances, we are unable to say that the
    juror misconduct did not prejudicially affect the outcome of the trial.”
    (Holloway, supra, 50 Cal.3d at p. 1112.)
    However, Juror No. 9‟s knowledge of defendant‟s convictions, standing alone, may not
    have been sufficiently prejudicial to warrant reversal. (People v. Ledesma (2006) 
    39 Cal.4th 641
    , 683 (Ledesma) [nothing incurably prejudicial about a jury learning that a
    defendant was previously convicted of the crime for which he was then on trial];
    Carpenter, 
    supra,
     9 Cal.4th at p. 655 [evidence that the defendant had been convicted of
    different but related crimes not prejudicial where evidence was overwhelming and the
    only fact the juror learned out of court was the verdict of the first jury].) But there is
    more.
    The prior appellate opinion quotes from the statement of facts contained in the
    earlier opinion (Pizarro I, supra, 
    10 Cal.App.4th 57
    ). The statement of facts from
    Pizarro I mentions that defendant testified in the first trial. He did not testify in the
    second trial, and the second jury was never informed that there had been an earlier trial or
    that defendant had testified in a previous trial. Surely, the defense did not want the
    second jury to know that defendant had previously been convicted or that he had testified
    in the first trial. While the jury was properly instructed that defendant had a
    constitutional right not to testify and that the jury was not to discuss this subject or
    penalize defendant for exercising that right, it is reasonable to project that, armed with the
    knowledge that defendant had been convicted in an earlier trial in which he testified, a
    juror would be inclined to think defendant chose not to testify in his second trial because
    39.
    the defense believed that his testimony in the first trial contributed to his earlier
    conviction. If this occurred in the mind of Juror No. 9, it certainly prejudiced defendant,
    but Evidence Code section 1150 precludes inquiry into Juror No. 9‟s mental processes.
    Prejudice is presumed from the misconduct. Again, by itself, the disclosure that
    defendant testified in the first trial may not be enough to establish prejudice warranting
    reversal. (Ledesma, 
    supra,
     39 Cal.4th at p. 683.) But there is more.
    On the subject of defendant‟s sobriety on the day of the crime, the prior appellate
    opinion states defendant had consumed beer throughout the afternoon and continued to
    drink at the party. When Sandy asked him to get into their truck, he behaved erratically,
    crisscrossing the road, lying in front of the truck and hiding from her. Later, he showed
    up at his mother‟s house and, according to his mother, appeared to be drunk. The People
    counter by citing testimony received in the second trial in which some witnesses said
    defendant did not appear intoxicated or he seemed to be handling his alcohol “okay.”
    The People miss the point. The question here is whether Juror No. 9 was substantially
    likely to have been prejudiced against defendant on the subject of his sobriety based on
    the prior appellate opinion‟s statement of the facts. That statement of facts leaves no
    doubt that the appellate court‟s review of the trial record led it to conclude that defendant
    was drunk. If the second trial evidence was in conflict on the issue, Juror No. 9 had the
    impression that a panel of appellate justices had concluded he was drunk. Thus, the
    People‟s claim that the extraneous information was presented to the jury anyway is not
    accurate. The jury was not told that an appellate court‟s review of the evidence led it to
    conclude that defendant was drunk. This information, judged objectively, was inherently
    and substantially likely to have influenced Juror No. 9 unless intoxication had nothing to
    do with the crimes, which leads us to the next related issue: motive.
    The prior appellate opinion reveals that defendant told an investigator that alcohol
    made him violent. This testimony was never mentioned in the second trial. Not only
    does this admission make relevant how much alcohol defendant had consumed at the
    40.
    time of the crime, it also furnishes an explanation for why this homicide even occurred.
    Defendant points out that the People offered no explanation for why he would harm his
    younger half-sister except for his intoxication and desire for sexual gratification, and that
    there was no evidence of any prior improper behaviors between them and no evidence
    that defendant had ever been violent. Therefore, defendant‟s admission that alcohol
    made him violent, coupled with the appellate court‟s conclusion that he was drunk at the
    time, supplies the necessary motivation or explanation for why defendant would commit
    such an abominable crime against his 13-year-old half-sister.
    The People point out that the defense attempted to use alcohol as a defense to
    minimize defendant‟s mental state. If so, defendant‟s admission in the first trial that
    alcohol made him violent becomes particularly prejudicial because the more the defense
    emphasized his intoxication as a mitigating factor, the more inculpatory his admission
    became. In other words, the admission that alcohol made him violent ran directly
    contrary to the defense position that his intoxication mitigated his culpability. Instead of
    minimizing his culpability, the admission explained his culpability. The prior appellate
    opinion‟s inclusion of this admission was potentially devastating to the defense in the
    mind of any juror who read it. Judged objectively, this admission was inherently and
    substantially likely to have influenced Juror No. 9. (Carpenter, 
    supra,
     9 Cal.4th at
    p. 653.) There is more.
    Most of the prior appellate opinion is devoted to a discussion of the DNA evidence
    in very technical and scientific terms. Aside from the complexities of that discussion, the
    opinion makes clear that the FBI conducted its own analysis of the DNA and concluded
    that the DNA from the sperm on the vaginal swabs matched the known blood sample of
    defendant. This court‟s opinion reversed the conviction because of flaws in the DNA
    testing procedures. The second trial made no mention of the FBI‟s DNA analysis or its
    conclusions. A reading of the prior appellate opinion‟s introduction or statement of the
    facts would inform the reader that the FBI‟s DNA analysis led it to conclude that
    41.
    defendant was Amber‟s assailant and killer. This was the same conclusion reached by
    the California DOJ, which years later conducted its own DNA analysis that was presented
    in the second trial. The prior appellate opinion‟s disclosure of the FBI‟s analysis and
    conclusion corroborated the conclusion of the DOJ and thereby created a substantial
    likelihood of juror bias. It likely lightened the prosecution‟s burden on convincing Juror
    No. 9 of the soundness of the DOJ‟s conclusions because a separate and nationally
    recognized crime lab analyzed the DNA and came to the same conclusion. This is
    analogous to an appellate court‟s reversing a conviction because an eyewitness‟s
    testimony should have been excluded and then having a juror in the second trial learn,
    through an extraneous and improper source, that there was an eyewitness who saw
    defendant commit the crime, but for technical legal reasons was not allowed to testify at
    the second trial. Judged objectively, the FBI‟s conclusion was inherently and
    substantially likely to have influenced Juror No. 9. (Carpenter, supra, 9 Cal.4th at
    p. 653.) There is still more.
    The prior appellate opinion also declares that the evidence presented a “„strong
    circumstantial case‟” against defendant. (Pizarro II, supra, 110 Cal.App.4th at p. 634.)
    Thus, Juror No. 9 sat through the balance of the trial with the knowledge that an appellate
    court believed the case against defendant was a strong one. Imagine if, on the second or
    third day of trial, a juror overheard a trial judge comment to someone off the record that
    the case against the defendant was a “„strong circumstantial case‟” (ibid.); or, even worse,
    if the trial judge made such a comment on the record in open court in front of the jury.
    Would not the defense have legitimate grounds to object and move for mistrial because of
    the understandable concern that the judge‟s comments would tend to influence the jury
    and thereby prejudice the defense? Would not such a comment, judged objectively,
    create a substantial likelihood that the jury would give some deference to the judge‟s
    implied opinion that the defendant was guilty or at least that the prosecution had met their
    burden of proof? Here, instead of the trial judge making such a comment, we have a
    42.
    three-judge appellate panel doing so in a formal appellate opinion. Judged objectively,
    this statement was inherently and substantially likely to have influenced Juror No. 9.
    (Carpenter, 
    supra,
     9 Cal.4th at p. 653.)
    These enumerated items of information, which were disclosed in the prior
    appellate opinion read by Juror No. 9, were not presented “to the [second] jury anyway,”
    as asserted by the People. Indeed, the trial court and counsel made special efforts to
    ensure that several of these matters were never revealed to the second jury. Juror No. 9‟s
    misconduct spoiled those efforts.
    b.      The Evidence of Guilt Was Not “Overwhelming”
    Second, the People contend that the evidence of defendant‟s guilt was “truly
    overwhelming” and therefore any juror misconduct was harmless. They cite Carpenter
    for the proposition that where the evidence is “„overwhelming,‟” the extraneous
    information cannot be considered inherently prejudicial. (Carpenter, supra, 9 Cal.4th at
    p. 655.)23 In Carpenter, the trial judge specifically found the evidence of guilt
    “„overwhelming,‟” but erroneously concluded that the extraneous information was
    inherently prejudicial without considering the entire record. (Ibid.) The judge also stated
    that the usual harmless error tests did not apply. (Id. at p. 644.) By contrast, in the
    instant case, the trial judge did not state the evidence of guilt was overwhelming. The
    Carpenter case was cited by the parties and mentioned numerous times during oral
    argument on the new trial motion and yet the trial judge never characterized the evidence
    as “„overwhelming‟” as a basis for denying the new trial motion. Instead, the trial judge
    23      Although the rule of Carpenter is that overwhelming evidence of guilt can rebut
    the presumption of prejudice in an inherent bias case, the opinion offers no definition or
    description of what constitutes overwhelming evidence of guilt. The opinion does not
    detail or summarize the prosecution‟s evidence, but merely quotes from the trial judge
    who found the evidence of guilt overwhelming. No guidance is offered as to how or
    when a “strong” prosecution case converts to one that is “overwhelming.”
    43.
    stated that the decision he had to make on the motion for new trial was “a close case” and
    “very, very hard.” Presumably, if the trial judge believed the evidence was
    overwhelming, he would have said so.24
    The People point to the DNA evidence (derived from sperm) as indicative that the
    evidence weighed strongly in favor of defendant‟s guilt. Such evidence, however, only
    established that defendant had sex with Amber within 72 hours of the homicide. It did
    not prove whether that sexual activity was consensual or accomplished by force. Indeed,
    the second jury acquitted defendant of the forcible rape charge. The DNA evidence did
    not establish that defendant had sex with Amber at or near the time she was killed or that
    he was with her at the time she was killed. The DNA evidence proved the statutory rape
    charge, but no more.
    While there was considerable circumstantial evidence that defendant committed
    the homicide, there were other evidentiary considerations that raised doubts about his
    guilt. For example, there were no eyewitnesses. There was no confession by defendant.
    The only blood found at the scene belonged to Amber. Not only was there no evidence
    that defendant had ever harmed his half-sister in the past or had a motive to do so, the
    uncontroverted evidence from their mother was that the two of them were “extra close”
    and defendant was “devastated” when he learned Amber was dead. There was evidence
    that Scott Nelson confessed to the crime.
    It took 10 days to present the evidence in this trial. The jury deliberated over the
    course of six days. During those six days, the jury requested further instruction on the
    24     We also note that the jury reported they were deadlocked (the record does not
    reveal how they were split in their voting) after several days of deliberation, which may
    suggest that the evidence was not overwhelming. After reporting they were deadlocked,
    Juror No. 7 was discharged for juror misconduct and replaced. Deliberations began anew
    and a verdict was later returned, but only after the newly constituted jury reported a
    deadlock on counts 2 and 3. Two reports of jury deadlock tend to refute the claim that
    the evidence of guilt was overwhelming.
    44.
    felony murder rule and additional attorney argument on numerous topics. The jury twice
    reported being deadlocked.25 These facts are not consistent with a case of overwhelming
    evidence of guilt.
    c.      Carpenter, Ledesma, Malone Do Not Require Affirmance
    Our decision does not run afoul of the authorities cited by the People. The People
    rely primarily on Carpenter, supra, 
    9 Cal.4th 634
    , Ledesma, 
    supra,
     
    39 Cal.4th 641
    , and
    In re Malone (1996) 
    12 Cal.4th 935
     (Malone) in support of the argument that
    Juror No. 9‟s misconduct in reading the prior appellate opinion does not require reversal.
    The qualitative and quantitative content of the extraneous material contained in the prior
    appellate opinion read by Juror No. 9 distinguishes this case from the cases cited by the
    People.
    In Carpenter, the high court reversed the trial judge‟s order granting a new trial. It
    upheld a capital conviction even though a juror received information that the defendant
    had been convicted of different but related capital crimes. The underlying facts of those
    related crimes were introduced in the trial, but jurors were not told the defendant had
    been convicted of those crimes. The Supreme Court held there was no inherent bias in
    light of the entire record, since the evidence was “„overwhelming‟” (quoting the trial
    judge) and since the only fact the juror “learned out of court was the verdict of the first
    jury.” (Carpenter, supra, 9 Cal.4th. at p. 655, fn. omitted.)
    This was not the case here. In addition to revealing that a prior jury had found
    defendant guilty of the same crime for which defendant was on trial, even a cursory
    reading of the prior appellate opinion uncovered several pieces of extraneous information
    that were harmful and perhaps devastating to the defense (DNA analysis performed by
    the FBI connected defendant to the crime, the appellate court described defendant‟s
    alcohol consumption that day and characterized the evidence against defendant as a
    25     See footnote 24, ante.
    45.
    strong circumstantial case, defendant testified in the first trial, defendant told police that
    alcohol made him violent). The Carpenter holding would be more analogous if
    Juror No. 9‟s outside research resulted in his learning that defendant had been previously
    convicted and nothing more. (See Ledesma, 
    supra,
     39 Cal.4th at p. 683 [“we do not
    presume that knowledge that a defendant previously has been convicted and is being
    retried is incurably prejudicial”].) Here there is so much more.
    Ledesma is similar to Carpenter. In Ledesma, after the defendant‟s first
    conviction was reversed, his second jury learned that he previously had been convicted
    and sentenced to death in the same case when a witness mentioned he had been on death
    row. (Ledesma, supra, 39 Cal.4th at pp. 681-682.) Like Carpenter, the Ledesma court
    concluded that there was nothing incurably prejudicial about a jury learning that a
    defendant was previously convicted of the crime for which he was then on trial.
    (Ledesma, 
    supra, at pp. 682-684
    .) Again, our case involves considerably more
    extraneous information than what was wrongfully disclosed in either Carpenter or
    Ledesma.
    Malone is also cited by the People, but its facts bear no resemblance to ours. In
    Malone, during jury deliberations, the foreperson expressed opinions about the
    defendant‟s polygraph evidence based on her own professional study. (Malone, 
    supra,
    12 Cal.4th at pp. 944, 963.) While this constituted misconduct, the court found the
    presumption of prejudice rebutted because the foreperson‟s comments were substantially
    the same as the evidence and argument presented to the jury. Since the extraneously
    derived information did not add to or detract from the actual evidence presented, the
    court found that no prejudice occurred. (Id. at pp. 964-965.) In our case, the prior
    46.
    appellate opinion did just the opposite—it supplied information that was never presented
    to the jury because it was deemed prejudicial against defendant.26
    4.     Holloway
    Holloway supports our conclusion. In Holloway, the Supreme Court reversed a
    death conviction. The trial judge denied mistrial and new trial motions based on
    discovery of jury misconduct after the jury returned guilty verdicts of first degree murder
    with special circumstances. During the trial, a juror had improperly read a newspaper
    account which disclosed that, at the time of the charged offenses, the defendant had been
    on parole for assaulting a woman with a hammer. The trial court had previously ruled
    that the defendant‟s parole status and prior offense were inadmissible. (Holloway, supra,
    50 Cal.3d at pp. 1106-1108.) The high court reversed the conviction, finding that the
    presumption of prejudice had not been rebutted. That single disclosure was enough for
    the court to find reversible prejudice. (Id. at pp. 1110-1111.) Here, there were multiple
    pieces of highly prejudicial information that Juror No. 9 obtained. Even if no single item
    was sufficiently prejudicial to warrant reversal, the combination of several items was.
    5.     Conclusion
    We conclude that the presumption of prejudice arising from Juror No. 9‟s
    misconduct was not rebutted. Accordingly, the trial court abused its discretion in
    denying defendant‟s motion for new trial. (People v. Staten (2000) 
    24 Cal.4th 434
    , 466;
    People v. Perez (1992) 
    4 Cal.App.4th 893
    , 906.) Although our resolution of this issue
    26     While we agree that a trial court‟s in limine ruling that evidence is inadmissible
    under Evidence Code section 352 (more prejudicial than probative) is different from
    deciding whether a jury‟s acquisition of that same information was prejudicial in light of
    the entire record (Holloway, supra, 50 Cal.3d at p. 1112; see also Carpenter, 
    supra,
     9
    Cal.4th at p. 655, fn. 2), it does not follow that such rulings are irrelevant on the subject
    of prejudice.
    47.
    dictates our reversal, we turn to issues regarding the DNA evidence that might be
    relevant in case of a retrial.
    II.    DNA EVIDENCE
    A.      Introduction
    When a perpetrator leaves his DNA behind after committing a crime—in this case,
    in the form of sperm—his genetic profile can be created from that DNA. When a suspect
    is identified, his genetic profile is analyzed and compared to the perpetrator‟s profile. If
    the suspect‟s profile matches the perpetrator‟s profile, the suspect becomes a possible
    perpetrator and the case against him may proceed. If the suspect‟s profile does not match
    the perpetrator‟s profile, the suspect is exonerated and the case against him is over.
    (Pizarro II, supra, 110 Cal.App.4th at pp. 541-542, 563; People v. Johnson (2006) 
    139 Cal.App.4th 1135
    , 1147.)
    In Pizarro II, we likened a genetic profile to a physical profile, where the suspect
    is found to share a number of the perpetrator‟s physical traits (rather than genetic loci)—
    such as hair color, eye color, and height—reported by an eyewitness. The match between
    their traits directly incriminates the suspect (who is now the defendant) by demonstrating
    that he resembles the perpetrator and therefore could be the perpetrator.27 But the match
    alone does not establish the weight of the evidence. Anyone with the same profile could
    be the perpetrator, and if a large number of people share the profile, the match does not
    carry much evidentiary weight. Thus, the match requires a second piece of evidence—
    the statistical frequency of the profile. “The statistical evidence gives the match evidence
    27     As we noted in Pizarro II, a match between the perpetrator‟s and the defendant‟s
    profiles “does not signify an absolute match between the entirety of the perpetrator‟s
    DNA and the entirety of the defendant‟s DNA, which would absolutely prove the
    perpetrator and the defendant are the same person. The match is actually between only a
    few or several regions of an enormous amount of DNA, and therefore it does not
    absolutely prove identity. What it does prove is that the defendant could be the
    perpetrator.” (Pizarro II, supra, 110 Cal.App.4th at p. 576.)
    48.
    its weight. It is an expression of the rarity of the perpetrator‟s profile, the size of the pool
    of possible perpetrators, and the likelihood of a random match with the perpetrator‟s
    profile.” (Pizarro II, supra, 110 Cal.App.4th at p. 542; see also id. at p. 576.) “The
    determination of what is often called the „significance of the match‟ is a statistical
    assessment of how incriminating it is that the defendant‟s profile matches the
    perpetrator‟s.” (Id. at p. 576.) The rarer the profile in the population, the more likely the
    defendant is in fact the perpetrator.28 (Id. at pp. 542, 576; see also People v. Johnson,
    
    supra,
     139 Cal.App.4th at p. 1147; People v. Venegas (1998) 
    18 Cal.4th 47
    , 82
    (Venegas); National Research Council, The Evaluation of Forensic DNA Evidence
    (1996) p. 127 (NRCII); National Research Council, DNA Technology in Forensic
    Science (1992) p. 44 (NRCI).)
    We turn to a brief summary of the science behind STR analysis, which takes
    advantage of the genetic phenomenon of STR‟s and is made possible by the molecular
    biology process called the Polymerase Chain Reaction (PCR).
    DNA‟s double helix is often compared to a twisted ladder. The side rails of the
    ladder are composed of a uniform sugar-phosphate backbone. The rungs of the ladder are
    made of the bases adenine, guanine, cytosine, and thymine (A,G,C, and T). The linear
    sequence of these four bases along the length of the ladder varies and makes up the
    28      Of course, as more traits are added to the perpetrator‟s profile, the profile‟s
    specificity and rarity increase, and the pool of possible perpetrators decreases.
    (Pizarro II, supra, 110 Cal.App.4th at p. 562.) For example, in 1989, in preparation for
    the first trial, the samples in this case were tested using RFLP analysis. Only three traits
    or loci made up the perpetrator‟s genetic profile, and the frequency of that profile was
    calculated to be approximately one in 10,000,000 Caucasians and one in 250,000
    Hispanics. (Id. at p. 552 & fn. 22.) In 2004, in preparation for the second trial, the
    samples were retested using the more modern STR analysis. This time, 13 loci made up
    the perpetrator‟s profile, and the frequency of that profile was calculated to be
    approximately one in 3.9 quintillion African-Americans, one in 350 quadrillion
    Caucasians, and one in 4.2 quadrillion Hispanics. The evidentiary weight of the second
    match increased astronomically.
    49.
    genetic code that gives DNA its meaning. Two bases form each rung and are bound
    together in the center in a complementary fashion—A binds to T, and G binds to C. The
    sugar-phosphate backbone rail is covalently bound, while the complementary bases
    coming together as rungs in the center are less tightly bound to one another by hydrogen
    bonds. This allows the linear halves of the ladder to separate for replication.
    Although most regions of DNA are identical from one person to the next, some
    regions vary in sequence and/or length. DNA analysis for the purpose of identification
    often relies on the comparison of these variable regions. STR‟s are stretches of DNA
    composed of repeated blocks of short sequences, often four nucleotides long. The
    number of repeats varies among people, usually within the range of 10 to 20 repeats. The
    function of these repetitive regions is unknown, but their variability provides an
    opportunity to identify differences between two people, such as perpetrator and suspect in
    a criminal case, or father and child in a paternity case.
    Because a person inherits a set of chromosomes (22 plus an X or Y) from each
    parent, every locus has two versions (alleles). These alleles can be the same or they can
    be different. In STR analysis, the number of repeats in an STR allele (reflected in the
    length of the allele) gives the allele its name/number. The results of the analysis are
    produced in a graph (electropherogram) that shows, for each locus, two peaks if the
    person‟s two alleles are different (heterozygous), or one larger peak, roughly twice the
    height of two heterozygous peaks, if the person‟s two alleles are the same (homozygous).
    For each peak, the electropherogram labels the allele repeat number and the height of the
    peak.
    Thus, if a person‟s two alleles at a particular STR locus are both the same length,
    for example 14 repeats long, the person‟s genotype is 14,14 and homozygous. If the
    person‟s alleles at a locus are different lengths, for example 14 and 19 repeats long, the
    person‟s genotype is 14,19 and heterozygous. Several STR loci are tested to create a
    genetic profile for the perpetrator and for any other relevant persons, such as the victim
    50.
    and any suspects. For two profiles to match, they must have the same alleles at every
    locus.29
    A tool critical to the implementation of STR analysis is PCR. PCR has
    revolutionized DNA analysis because it is capable of making millions of copies of a
    target segment of DNA. Thanks to PCR, very small amounts of DNA—theoretically, just
    one piece—can be copied (amplified) exponentially to produce sufficient target DNA for
    analysis. This is critical in forensic work where sometimes only trace amounts of DNA
    can be collected.
    PCR‟s three-step amplification cycle occurs in a very small tube containing a
    sample of the double-stranded DNA with the target segment (e.g., the evidence DNA),
    short single-stranded pieces of DNA (primers) designed to bind to the two specific
    regions flanking the target segment of DNA (primer binding sites), a heat-resistant DNA-
    building enzyme (a DNA polymerase), the building blocks of DNA (nucleotides),30 and
    other required elements. The tube is placed in a thermal cycler for amplification. In the
    first step, the temperature is elevated to near-boiling to separate (denature) the double-
    stranded DNA into single strands, breaking the hydrogen bonds between bases and
    exposing the two template strands to the primers. Second, the temperature is lowered
    until the primers are able to bind (anneal or hybridize) to the primer binding sites on the
    single-stranded template DNA. Third, the temperature is elevated slightly and the DNA
    polymerase synthesizes (extends) DNA from the end of each primer to make a new strand
    of DNA complementary to the template strand. These new strands serve as additional
    templates in the following cycles, rendering the amplification exponential. In the first
    29     The STR loci are generally named with letters and numbers that describes their
    location on a chromosome (e.g. D8S1179, D21S11); others are named with an
    abbreviation for the name of the gene they are found within (e.g., TPOX is located within
    the thyroid peroxidase gene; FGA is located within the alpha fibrinogen gene).
    30     A nucleotide consists of a base and its connected sugar and phosphate molecules.
    51.
    few cycles, some long strands are created, but eventually the region bounded by the two
    primers becomes the overwhelmingly predominant product. This thermal cycle is
    repeated about 30 times to create an enormous number of copies of the target region. It is
    by this method that the STR loci are targeted within a person‟s DNA and amplified so
    they can be ascertained by observable means, even if the original forensic sample
    contains very little DNA.
    In this case, Myers used the Profiler Plus and COfiler kits and the Prism 310
    Genetic Analyzer (the 310 Analyzer), all manufactured by Applied Biosystems, Inc.
    (ABI), to analyze the 13 STR loci, which had been chosen by the scientific community as
    the core loci for STR analysis, as well as the X and Y chromosomes for sex
    identification.
    At trial, defendant challenged the admissibility of the DNA evidence and
    requested a hearing pursuant to Kelly, supra, 
    17 Cal.3d 24
    . The Kelly test is an
    evidence-screening device for sophisticated scientific evidence that tends to be highly
    convincing, but not readily understood by lay jurors. (Pizarro II, supra, 110 Cal.App.4th
    at p. 555.) “In the Kelly review process, the trial judge serves as gatekeeper, allowing
    only evidence that is sufficiently reliable and trustworthy to reach the jurors.” (Ibid.)
    Because of the immense power of scientific evidence, the Kelly test goes to the
    admissibility, not the weight, of the evidence. (Kelly, supra, at pp. 30-32.)
    Kelly explained its three-prong test as follows: “(1) the reliability of the method
    must be established, usually by expert testimony, and (2) the witness furnishing such
    testimony must be properly qualified as an expert to give an opinion on the subject.
    [Citations.] [(3)] Additionally, the proponent of the evidence must demonstrate that
    correct scientific procedures were used in the particular case. [Citations.]” (Kelly, supra,
    17 Cal.3d at p. 30; Venegas, 
    supra,
     18 Cal.4th at p. 78.)
    In defendant‟s 105-page Kelly motion to exclude the DNA evidence, he argued
    that (1) a first-prong hearing was required (a) on the general acceptance of the mixture
    52.
    interpretation procedure and (b) on the general acceptance of the STR procedure because
    he was offering evidence that undermined its reliability, and (2) a third-prong hearing
    was required to establish that correct scientific procedures were used in this case. The
    trial court refused to hold a first-prong hearing, concluding that a number of published
    cases had already determined the general acceptance of the STR procedure. The court
    did agree, however, to hold a third-prong hearing, and it concluded that correct scientific
    procedures had been followed in this case.
    B.     Kelly’s First Prong*
    Under the first prong of Kelly, a new scientific method is considered reliable when
    it has attained acceptance in the relevant scientific community. (Kelly, supra, 17 Cal.3d
    at pp. 30-32 [noting California had adopted this test from the federal case of Frye v.
    United States (D.C. Cir. 1923) 
    293 Fed. 1013
     (Frye)]31.) “Kelly „does not demand that
    the court decide whether the procedure is reliable as a matter of scientific fact: the court
    merely determines from the professional literature and expert testimony whether or not
    the new scientific technique is accepted as reliable in the relevant scientific community
    and whether “„scientists significant either in number or expertise publicly oppose [a
    technique] as unreliable.‟” [Citations.]‟ [Citation.] „“General acceptance” under Kelly
    means a consensus drawn from a typical cross-section of the relevant, qualified scientific
    community.‟ [Citation.]” (People v. Soto (1999) 
    21 Cal.4th 512
    , 519.)
    The question of general scientific acceptance may be answered by prior case law:
    “[O]nce a trial court has admitted evidence based upon a new scientific technique, and
    *      See footnote, ante, page 1.
    31      “Until 1993, [the Kelly test] was generally known in this state as the Kelly-Frye
    [test] because this court in Kelly had relied on the reasoning of [Frye]. In 1993, the
    United States Supreme Court held that the Federal Rules of Evidence had superseded
    Frye [citation], and our state law rule is now referred to simply as the Kelly test or rule.
    [Citation.]” (People v. Bolden (2002) 
    29 Cal.4th 515
    , 545.)
    53.
    that decision is affirmed on appeal by a published appellate decision, the precedent so
    established may control subsequent trials, at least until new evidence is presented
    reflecting a change in the attitude of the scientific community.” (Kelly, supra, 17 Cal.3d
    at p. 32; Venegas, 
    supra,
     18 Cal.4th at p. 53.) Thus, a defendant is not foreclosed from
    showing that a scientific test has since been invalidated or that there has been a change in
    the consensus of the scientific community concerning the test. (People v. Allen (1999) 
    72 Cal.App.4th 1093
    , 1100-1101; People v. Smith (1989) 
    215 Cal.App.3d 19
    , 25.)
    We independently review the trial court‟s first-prong rulings on general
    acceptance. (Venegas, 
    supra,
     18 Cal.4th at p. 85.) “[I]n reviewing the scientific
    acceptance of [a method] de novo under Kelly, we are not required to decide whether [it]
    is „reliable as a matter of “scientific fact,” but simply whether it is generally accepted as
    reliable by the relevant scientific community.‟ [Citation.]” (Ibid.)
    C.     Refusal to Hold First-Prong Kelly Hearing*
    Defendant contends the trial court erred in refusing to hold a first-prong Kelly
    hearing. He concedes that the exact type of testing performed in this case, including use
    of the Profiler Plus and COfiler kits and the 310 Analyzer, had already been found
    generally accepted under Kelly‟s first prong by People v. Smith (2003) 
    107 Cal.App.4th 646
    , 671-672 (Smith) (analysis of mixed DNA sample “by means of short tandem repeats
    utilizing Profiler Plus and COfiler in conjunction with the … 310 Genetic Analyzer is
    accepted by the scientific community”) and People v. Henderson (2003) 
    107 Cal.App.4th 769
    , 776, 789 (Henderson) (in STR analysis, using Profiler Plus and COfiler kits in
    conjunction with the 310 Analyzer, capillary electrophoresis is generally accepted by
    scientific community), but he claims the evidence he presented to the trial court
    undermined the continuing reliability of the STR technology and revealed a change of
    consensus within the scientific community concerning the technique. He explains that
    *      See footnote, ante, page 1.
    54.
    the 38 exhibits he presented to the trial court contained data and publications that either
    were not available at the time of Smith and Henderson or were not considered in Smith
    and Henderson. According to defendant, the exhibits proved that various studies found
    significant reliability problems with the Profiler Plus and COfiler kits and the
    310 Analyzer.
    First, we note that cases more recent than Smith and Henderson have reiterated the
    continued acceptance of the STR analysis by the scientific community. Recently, the
    court in People v. Stevey (2012) 
    209 Cal.App.4th 1400
     determined that STR testing of the
    Y chromosome did not require a first-prong Kelly hearing:
    “As the Attorney General points out, California courts have found
    that the use of PCR and STR technology has been generally accepted by the
    scientific community. (Smith, supra, 107 Cal.App.4th at p. 665;
    Henderson, supra, 107 Cal.App.4th at pp. 786-787.) In both cases the court
    refused to undertake a Kelly prong-one hearing to determine whether use of
    the technology in mixed-source cases specifically had been accepted by the
    scientific community. And in both cases, the courts recognized the
    additional complications arising from mixed-source samples that might
    impact on the results‟ reliability, but concluded that the weaknesses or
    potential flaws were considerations for the jury in weighing the evidence
    and determining the accuracy of the results. (Smith, supra, 107
    Cal.App.4th at pp. 671-672; Henderson, supra, 107 Cal.App.4th at p. 788.)
    These complications did not trigger the need for a Kelly evidentiary
    hearing. [Citation.]” (People v. Stevey, supra, at p. 1418.)
    In 2008, the court in People v. Jackson (2008) 
    163 Cal.App.4th 313
     recognized
    that STR analysis was generally accepted and concluded that new STR kits need not be
    subjected to first-prong scrutiny to determine scientific reliability:
    “The DNA amplification in this case was performed by the
    PCR/STR method. This methodology has been found to be generally
    accepted in the scientific community. (People v. Hill (2001) 
    89 Cal.App.4th 48
    , 57 (Hill); People v. Allen (1999) 
    72 Cal.App.4th 1093
    ,
    1100.) In addition, capillary electrophoresis, the procedure used to analyze
    the amplified DNA fragments, has been found to have gained general
    acceptance in the scientific community. (People v. Henderson[, supra,]
    107 Cal.App.4th [at p.] 789.)” (People v. Jackson, supra, at p. 324.)
    55.
    Second, we conclude that the exhibits defendant presented to the trial court do not
    prove the STR method is no longer generally accepted by the scientific community. In
    these 38 exhibits, which we have reviewed, there is certainly evidence of valid issues and
    ongoing concerns about flaws in the STR system, such as allelic dropout (which we
    address below), but no evidence that the community has rejected STR analysis as
    unreliable or no longer generally accepts the method as reliable or acceptable. In fact, it
    remains the standard applied to forensic DNA analysis.
    The phenomenon of allelic dropout and null alleles has been known for many
    years and defendant‟s exhibits support the conclusion that the STR procedure remains
    generally accepted despite allelic dropout. Based on the lack of evidence that the
    scientific community no longer generally accepts the STR procedure as reliable, we
    conclude the trial court did not err in refusing to hold a first-prong Kelly hearing. (See
    Kelly, supra, 17 Cal.3d at p. 32; Venegas, 
    supra,
     18 Cal.4th at p. 76.)
    D.     Kelly’s Third Prong*
    The third Kelly prong asks: Were the proper scientific procedures followed in this
    particular case? (Venegas, 
    supra,
     18 Cal.4th at p. 78; Pizarro II, supra, 110 Cal.App.4th
    at p. 554.) “The Kelly test‟s third prong does not apply the Frye requirement of general
    scientific acceptance—it assumes the methodology and technique in question has already
    met that requirement. Instead, it inquires into the matter of whether the procedures
    actually utilized in the case were in compliance with that methodology and technique, as
    generally accepted by the scientific community. [Citation.] [¶] … [¶] [Q]uestions
    concerning whether a laboratory has adopted correct, scientifically accepted procedures
    for [DNA testing] or determining a [profile] match depend almost entirely on the
    technical interpretations of experts. [Citation.] Consideration and affirmative resolution
    *      See footnote, ante, page 1.
    56.
    of those questions constitutes a prerequisite to admissibility under the third prong of
    Kelly.” (Venegas, 
    supra, at pp. 78-81
    .)
    Although Kelly‟s first two prongs apply to a new scientific procedure (Kelly,
    supra, 17 Cal.3d. at p. 30), the third prong applies even to evidence derived from a
    long-standing scientific procedure that has already been found to have attained general
    acceptance. (Venegas, 
    supra,
     18 Cal.4th at p. 79 [whether specific steps in FBI‟s analysis
    were in compliance with long-standing and accepted methods presented questions of
    correct scientific procedures properly considered under third prong].)
    “The Kelly test‟s third prong does not, of course, cover all derelictions in
    following the prescribed scientific procedures. Shortcomings such as mislabeling,
    mixing the wrong ingredients, or failing to follow routine precautions against
    contamination may well be amenable to evaluation by jurors without the assistance of
    expert testimony. Such readily apparent missteps involve „the degree of professionalism‟
    with which otherwise scientifically accepted methodologies are applied in a given case,
    and so amount only to „[c]areless testing affect[ing] the weight of the evidence and not its
    admissibility‟ [citations].” (Venegas, supra, 18 Cal.4th at p. 81.)
    “„“All that is necessary in the limited third-prong hearing is a foundational
    showing that correct scientific procedures were used.” [Citation.]‟ [Citation.] Where the
    prosecution shows that the correct procedures were followed, criticisms of the techniques
    go to the weight of the evidence, not its admissibility. [Citations.]” (People v. Brown
    (2001) 
    91 Cal.App.4th 623
    , 647 (Brown).) Similarly, where there is substantial evidence
    showing both that procedures were followed and that they were not followed, the
    question is one for the jury to resolve. (Venegas, 
    supra,
     18 Cal.4th at p. 91.) But where
    defense evidence establishes a failure in procedure, and that failure is not contradicted by
    substantial evidence, then the evidence produced as a result of that incorrect procedure is
    inadmissible. (See id. at pp. 91-93.)
    57.
    In contrast to first-prong issues, the trial court‟s third-prong conclusions that
    proper procedures were followed in a particular case are reviewed for abuse of discretion.
    (Venegas, 
    supra,
     18 Cal.4th at p. 91.) The appellate court is “required to accept the trial
    court‟s resolutions of credibility, choices of reasonable inferences, and factual
    determinations from conflicting substantial evidence. [Citation.]” (Ibid.) “We thus
    consider whether there is substantial evidence in the record to support the conclusion that
    the procedures were in fact performed in a manner fully consistent with the underlying
    science such that they produced reliable results. [Citation.]” (Pizarro II, supra, 110
    Cal.App.4th at p. 559.)
    E.     Failure To Follow Correct Procedures Under Kelly’s Third Prong
    Defendant contends the trial court abused its discretion when it determined that
    correct scientific procedures had been followed in this case. The following evidence was
    elicited at the Kelly hearing.
    1.      Steven Myers’s Testimony
    a.     Introduction
    Steven Myers, a highly trained senior criminalist at the DOJ lab in Richmond,32
    testified that he began his DNA analysis of the evidence in this case in November 2004.
    He analyzed the DNA on the vaginal swabs and found a mixture of sperm cell DNA and
    epithelial cell DNA. He created a 13-loci genetic profile for the perpetrator (the major
    contributor from the vaginal swab‟s sperm cell fraction). When he later analyzed the
    DNA from defendant‟s reference blood sample, he found that it matched the alleles at all
    13 of the loci of the perpetrator‟s profile. Myers‟s statistical analysis established that the
    estimated frequency of that profile, or the chance that a randomly chosen person would
    have that profile, was approximately one in 3.9 quintillion African-Americans, one in
    32     Henceforth, the lab, the DOJ lab, and the DOJ refer to the Richmond DOJ lab
    unless otherwise noted.
    58.
    350 quadrillion Caucasians, and one in 4.2 quadrillion Hispanics. Myers also analyzed
    Amber‟s reference blood sample and found that it matched the alleles at all 13 loci of the
    epithelial cell fraction from the vaginal swab.
    b.     Victim Sexual Assault Kit*
    The victim sexual assault kit contained a sealed envelope holding a vaginal swab.
    This was the only vaginal swab Myers tested. The vaginal swab bore initials that Myers
    recognized as belonging to Delia Frausto-Heredia from the DOJ‟s Fresno lab. Myers
    chose to test this swab because he believed it had “gone fewer places,” had “had the least
    done” to it, and had been subjected to “less movement around the country” than the other
    swabs. It appeared to Myers that about one-third of the swab had been sampled
    previously.33
    On cross-examination, Myers testified that the swab contained a large quantity of
    sperm, particularly for the age of the sample. In his opinion, this large quantity of sperm
    would not be transferrable by contamination, as defense counsel proposed. But Myers
    agreed that, hypothetically, contamination of a vaginal swab could occur if the analyst
    touched the end of the swab with a contaminated finger, or if the analyst examined
    semen-stained underwear at the same time as the vaginal swab. But the analyst would
    have to place his contaminated finger directly on the end of the swab, and the sperm
    would not transfer in a large quantity because the swab would be dry. Myers stressed
    that although the swab was originally analyzed many years ago, labs at that time were
    cognizant of contamination issues. Myers did not believe it was likely that the vaginal
    *      See footnote, ante, page 1.
    33    On cross-examination, Myers stated that he believed this swab had stayed in the
    Fresno lab and the other three vaginal swabs had been sent to the FBI. A letter written to
    the FBI by Frausto-Heredia accompanying the samples to be analyzed stated that three
    vaginal swabs were being sent; the third already had been analyzed. Myers chose to
    analyze the swab that had stayed in the Fresno DOJ lab.
    59.
    swab in this case had been contaminated with sperm from defendant‟s underwear,
    especially with the large amount of sperm on the swab. And if someone had
    contaminated the swab by dipping it into fresh semen, it probably would contain even
    more sperm than it did.
    On direct examination, Myers explained that in the next step of the analysis, he
    returned the swab material to the tube with the cellular material. He added various
    chemicals, including an enzyme to break open the cell membranes and lyse the non-
    sperm cells (i.e., the vaginal epithelial cells), but not the hardier sperm cells After a two-
    hour incubation at a high temperature, Myers shook the swab material again, removed it,
    and stored it in the freezer. After centrifugation of the tube, a cell pellet was formed with
    a solution above it. Myers expected the cell pellet to contain sperm cells and the solution
    above it to contain the lysed epithelial cells and their contents (including DNA). After he
    removed and saved the solution, Myers examined the cells in the pellet and realized the
    pellet contained some epithelial cells that had not been lysed. He repeated the lysing
    procedure, after which it appeared all the epithelial cells had been lysed.
    To the sperm cell pellet, Myers added chemicals, including dithiothreitol (DTT),
    to lyse the hardier sperm cells. After this step, Myers had two solutions of lysed cells,
    one containing epithelial cell DNA and the other containing sperm cell DNA. He
    extracted the DNA from the solutions and quantitated how much DNA was in each
    extraction.
    After Myers removed the cells from the vaginal swab and attempted to separate
    the epithelial cells from the sperm cells, he used ABI‟s Profiler Plus and COfiler kits to
    amplify 13 STR loci and a sex identification locus. The kits included fluorescent primers
    specific to areas on the DNA containing the STR loci. Myers tested the samples in this
    case separately from samples in any other case.
    After PCR, Myers separated the PCR products (DNA pieces) by size with the
    310 Analyzer, a capillary electrophoresis instrument. The solution containing the various
    60.
    PCR products was loaded (injected) at one end of the capillary tube and the pieces of
    DNA traveled through a polymer in the tube, drawn by an electrical charge. DNA pieces
    of the same size traveled together, and each piece‟s fluorescent tag was recorded as it
    passed a laser window. The 310 Analyzer measured the amount of time until the DNA
    pieces reached the laser window, which reflected their lengths, and also the amount of
    fluorescence they generated, measured in relative fluorescence units (RFU), which
    reflected the number of copies of each length. Samples of a known allelic ladder
    (standardized pieces of DNA of various known sizes) and controls were also analyzed for
    comparison. GeneScan and Genotyper software, also manufactured by ABI, analyzed
    these data to estimate the length of the DNA pieces and the number of repeats in each
    piece. The software produced an electropherogram, a graphical display with colored
    peaks rising from a baseline, and assigned to each peak a number of repeats (made an
    “allele call”) and an RFU count.
    On cross-examination, Myers explained that with GeneScan the analyst could set
    an RFU below which peaks would not be identified. This eliminated peaks that were
    consistent with stutter, a phenomenon where an extra, shorter copy of an allele is copied
    during PCR, in addition to the correct copy. This shorter copy is usually one repeat unit
    (e.g., four nucleotides) shorter than the correct copy. When GeneScan‟s threshold filter
    was turned off, the peaks below the threshold would reappear. ABI recommended using
    a threshold of 150 RFU and, below that, interpreting with caution. The DOJ‟s threshold
    was 75 RFU, but Myers generally set the threshold at 50 RFU for completeness,
    especially with mixed samples. He did, however, only call or identify alleles that were at
    least 75 RFU. After GeneScan detected and labeled all peaks above the 50 RFU
    threshold, Genotyper examined those peaks a second time and removed the labels if one
    of the two peaks at a locus was less than 15 percent the height of the other, a situation
    that supported a finding of stutter.
    61.
    c.      Mixture Interpretation*
    From the resulting electropherograms, it was immediately evident to Myers that
    the sperm cell fraction contained a mixture of more than one person‟s DNA. In other
    words, the separation of sperm and epithelial cells had not been complete. When Myers
    looked at the allele peaks and their intensities at each locus, he determined that the results
    were consistent with a major contributor, plus some epithelial DNA carryover as a minor
    contributor. All of the controls tested as expected, and there was nothing about the
    results that suggested any mistakes had been made. At this point, knowing he would
    have to interpret the mixture, Myers amplified the sperm cell fraction three more times to
    remove any variability issues.
    Myers explained that the DOJ‟s general interpretation guidelines included a
    protocol for interpreting a two-person mixture in which one person can be assumed to be
    the minor contributor. He explained that the goal in STR mixture interpretation is to
    determine the major contributor‟s alleles by assessing the minor contributor‟s alleles and
    the peak height ratios. Mixture interpretation can involve a lot of ambiguity because
    subtle variations in the major contributor can effectively hide the minor contributor‟s
    profile. But where the difference between the contributors is fairly significant, the minor
    contributor‟s alleles can be subtracted from the mixture, making the major contributor‟s
    alleles fairly obvious. When the DNA source is a vaginal swab, the minor contributor to
    the mixture can be assumed to be the victim‟s vaginal epithelial cells if the alleles from
    the victim match alleles in the mixture.
    This was the situation in this case. The difference between the contributors was
    significant, and the minor contributor‟s alleles matched those in the vaginal epithelial cell
    fraction. Accordingly, the minor contributor‟s alleles could be subtracted from the
    *      See footnote, ante, page 1.
    62.
    mixture to reveal the major contributor‟s alleles. This mixture interpretation was
    consistent with DOJ protocols and procedures.
    On cross-examination,34 Myers explained that it was because of the potential
    variability in PCR that he amplified the DNA in this case three additional times to ensure
    that the imbalances he saw in the mixture the first time were not due to a rare occurrence,
    as he explained below. He injected the results of each amplification into the 310 Analyzer
    twice, creating eight electropherograms. He calculated peak height ratios at each locus by
    setting the highest peak as 100 percent and determining the percentage of this height for the
    other peaks. Then he averaged the peak height ratios of the eight injections. Myers stated
    that the DOJ‟s STR protocol did not mention using an averaging method. Nor did he think
    either the ABI user manual or the FBI‟s STR protocol mentioned it. Myers had not seen
    anyone average profiles in the manner he had in this case.
    Myers explained that STR mixtures are inherently more difficult to interpret than
    single-source samples. The results from a single-source sample represent the profile
    from a single person, but in a mixed sample, where the composition of the mixture may
    be unknown, there may be ambiguity regarding which alleles come from which person.
    Theoretically, a person‟s two alleles at a locus should amplify consistently and in exactly
    equal numbers, producing two peaks of equal height and a peak height ratio of
    100 percent. In reality, the two alleles are usually well-balanced with a peak height ratio
    of at least 70 percent (the height of the shorter peak is at least 70 percent the height of the
    taller peak). But more peak variability and imbalance can occur for various reasons, and
    they greatly complicate mixture interpretation.
    Myers explained that although the mixture in this case contained three alleles at
    the D3S1358 locus, he determined that one peak was not the major contributor‟s because
    it was only about 20 percent of the shorter major peak. With an intimate sample such as
    34     Until otherwise noted, the following facts were elicited during cross-examination.
    63.
    a vaginal swab, incomplete separation of the mixture is not uncommon, and he proceeded
    with his interpretation based on the assumption that the minor contributor was from
    carryover from the epithelial portion of the vaginal swab.
    The DOJ written guidelines on mixture interpretation stated that a sample could be
    considered a mixture of major and minor contributors if there was a distinct contrast in
    peak heights among the alleles. The guidelines set no absolute threshold for what was
    considered a distinct contrast. Theoretically, two analysts could disagree on that
    question, but Myers was highly doubtful any disagreement could occur in this case.
    d.     Low DNA or Degraded DNA*
    When the initial amount of DNA amplified is extremely low, there will be more
    variability in the peak height ratio due to stochastic or chance effects. For example, a
    peak imbalance can occur when the sample of template DNA added in the PCR reaction
    contains, by chance, a few more copies of one allele than the other. With very low
    quantities of template DNA, an allele of a heterozygote can drop out entirely.
    Similarly, with severely degraded DNA samples, larger alleles may not amplify as
    well as the smaller alleles because the long stretches of DNA making up the larger alleles
    are more likely to be broken. In this case, Myers found that the DNA was somewhat
    degraded, which he expected because the sample was taken postmortem and was many
    years old.
    As the amount of template DNA diminishes, the chance of these irregularities
    increases. Different amplifications of the same template DNA can produce different peak
    heights. Myers had observed peak height ratios as low as 35 percent in low-DNA
    samples that otherwise amplified normally. In those cases, he did not call major and
    minor contributors because he knew these imbalances could occur with very low levels of
    template DNA.
    *      See footnote, ante, page 1.
    64.
    e.      Allelic Dropout and Null Alleles
    Myers explained on cross-examination that if the PCR amplification process itself
    does not occur equally at both alleles, the peak heights will be different. This could
    occur, for example, if one allele gets a jump-start in the amplification, or if one allele
    cannot be amplified as effectively as the other due to a sequence variation that prevents a
    PCR primer from annealing properly to the template DNA. The most extreme form of
    allele or peak imbalance occurs in the null allele phenomenon, a fairly rare event in
    which one of the two alleles simply does not amplify and therefore does not appear as a
    peak on the electropherogram (the allele “drops out”). The phenomenon is fairly rare
    because most people have the same sequence in these regions, but occasionally people
    will have a single base difference in the sequence. The sequence difference can affect the
    binding of a PCR primer to the template DNA‟s primer binding site in a critical way,
    such as when the mismatch occurs at the end of the primer where DNA extension will be
    initiated. If the instability is great enough to prevent copying of that allele, the missing
    peak will suggest that the allele does not exist. Myers believed null alleles occurred in
    about one in 1,000 profiles. He explained that null alleles are more common at certain
    loci. He was aware that null alleles had been found to occur more commonly at the
    D8S1179 locus in the Chamorro population.
    Myers was familiar with the studies demonstrating that ABI kits and Promega kits
    produced different null allele results. In some cases, one kit amplified one allele and the
    other kit amplified two alleles, either balanced or imbalanced. Defense counsel asked
    whether this could lead to a missed exclusion if, for example, the perpetrator were not
    really a homozygous 8,8 at the TPOX allele and thus defendant‟s 8,8 would not be a
    match. Myers responded: “But the person who would have that sample would still type
    as this same result using this kit. So as long as everyone is typed with the same kit there
    wouldn‟t be any false result because the result would be the same.” Defense counsel
    pursued the topic and the following exchange took place:
    65.
    “Q. Let me see if I follow that. Let‟s assume for the moment your
    testing shows—using the [ABI] Profiler Plus kit [defendant] is [an] 8[,]8 [at
    the TPOX locus], right?
    “A.    That is correct.
    “Q. If the [evidence] sperm sample is in fact an 8[,]9 and in fact
    [defendant] is an 8[,]8, your conclusion would be that he‟s excluded as a
    possible source for the sperm sample; isn‟t that true?
    “A. If the [perpetrator] is an 8[,]9 that would actually type as an
    8[,]9, then [defendant] would be obviously excluded.
    “Q.    Because?
    “A. If [the perpetrator is] … [an] 8[,]9 that types as [an] 8[,]8,
    then everyone who has just the [8] allele visible type with this kit would be
    included.
    “Q. Right. So what you‟re saying then is hypothetically if you
    type them with the [ABI] Profiler Plus kit as [an] 8[,]8 and you typed this
    [evidence] sperm sample [as an] 8[,]8, … in context with that loc[us],
    [defendant] is not excluded, right?
    “A.    That is correct.
    “Q. That hypothetically if I, as a defense lawyer, chose to go out
    and type [defendant] with the Promega kit and I [typed him as an] 8[,]9,
    then what would your conclusion be? Excluded or included?
    “A. My conclusion would be also that you need to type the
    evidence [sperm sample] now using the Promega kit to see what the
    evidence would type out as.
    “Q.    So the results would vary depending on what kit you used?
    “A.    They should be internally consistent within a kit.
    “Q. So your testing procedure cannot determine whether [a null]
    allele is present or not just using that kit?
    “A. Well, there are instances where we can have a good indication
    a [null] allele is present. Because, for example, we know that general
    balance between the loci. And if we see at a locus that a single allele was
    detected, but at a much lower level than normal productibility, that is an
    66.
    indication that you have a [null] allele present. But in instances where you
    have degradation[,] that gets more difficult.
    “Q.    You have degradation in this case?
    “A.    There is some in this case, yes.”
    Myers agreed that although null alleles are rare, they are increasingly being
    discovered over time. Myers was familiar with the following statement from John M.
    Butler‟s 2005 book, Forensic DNA Typing: Biology, Technology, and Genetics of STR
    Markers (Butler 2005), at page 135: “A number of primer concordance studies have been
    conducted in the past few years as use of various STR kits has become more prevalent.
    An examination of over 2,000 samples comparing the [Promega] Powerplex 16 kit to the
    [ABI] Profiler Plus and COfiler kit results found 22 examples of allele dropout due to a
    primer mismatch at seven of the 13 core STR loci .…”
    Myers made the assumption that allelic dropout had not occurred at the loci that
    produced a single peak—vWA, TPOX, and CSF1PO. He explained that because he saw
    no indication of allelic dropout such as a sudden decline in peak height, he made the
    assumption that the single peak represented a homozygous genotype “based on what is
    the most common event.”
    Myers explained that, at the vWA locus, he typed the evidence sperm DNA as a
    17,17, even though the electropherogram for the sperm DNA showed a small 16 peak in
    addition to the 17 peak. He agreed that if the evidence sperm DNA were actually a 16,17
    heterozygote, rather than a 17,17 homozygote, defendant would be excluded as a
    contributor because he was a 17,17 homozygote. In two of the eight runs of the evidence
    sperm DNA, the 16 peak was too small to be labeled by the software. In the other six
    runs, Myers had marked the 16 peak as inconclusive.
    Myers explained that his determination that the 16 allele was inconclusive did not
    mean there was no 16 allele present. In fact, in this mixed sample, a 16 allele was
    consistent with carryover due to incomplete separation of the epithelial DNA. But the
    67.
    vWA profile was not consistent with a typical sperm contributor with a 16,17 genotype
    because the imbalance between the alleles was too dramatic for a typical person‟s DNA.
    The two alleles, one from each parent, are generally present in equal amounts in the
    DNA, and when those alleles are amplified, fairly similar amounts of each allele are
    expected. Thus, the resulting peak heights for the alleles are also fairly similar, often
    within 80 percent of each other, and usually within 70 percent. Occasionally, the
    imbalance is greater, but this generally occurs with very low amounts of template DNA
    (causing stochastic or chance effects), genetic anomalies, and jump-starts in the copying
    of one allele. In cases like this with ample template DNA, Myers would never expect
    these two peaks to be from a typical heterozygote (16,17) contributor.
    On redirect examination, Myers explained that at the vWA locus, the 16 peak was
    so much smaller than the 17 peak that in the vast majority of situations it would not be
    consistent with being from a single donor. But it would be consistent with a mixture due
    to incomplete separation of sperm and epithelial DNA. The profile of the epithelial
    fraction was a 16,17 at the vWA locus and the alleles were almost perfectly balanced in
    peak height, which one would expect with a heterozygote.
    f.     Same Length but Different Sequence Alleles
    On cross-examination, Myers agreed that the STR procedure measures the length
    of a DNA piece, not its sequence, and he agreed that a person whose allele matches in
    length but not in sequence is not a match:
    “Q. Do you accept the proposition that someone who has this
    same length DNA but different sequences is not the same individual?
    “A.    Yes.
    “Q. In other words, if I have a length—just using an example,
    length 16, but my sequence is a CTG [cytosine-thymine-guanine] and
    [defendant] has that same loci 16, but his sequence is not a CTG, but some
    other sequence, your conclusion would be that those two samples did not
    come from the same individual?
    68.
    “A. No. Barring any kind of mutation that occurred within the
    body, etcetera, etcetera, yes. Just as a generality you can have this same
    length in a piece of DNA and still have two sequences. And studies have
    looked at families of repeat where you could see one set of lengths came
    from the same sequence family and at the same locus a similar length could
    be from a different sequence family. So that‟s documented, certainly.
    “Q. And are you familiar with Dr. Butler‟s discussion of this issue
    in [Butler 2005] under a heading called „Same Length, But Different
    Sequence Alleles.” Page 131. [¶] … [¶] Then if you turn to page 562 of
    the book, actually lists there, does he not, all of the—and let me back up.
    [¶] … [¶] What he‟s discussing there is the fact that people are finding that
    at certain of the loci that are typically tested—STRs typically tested there
    are alleles that have exact same length but different sequences, correct?
    Right?
    “A. That‟s part of it. He also says this—this is important, it is
    important to realize that from an operational point of view internal allele
    variation is not significant. Then goes on to say because we are talking
    about possible loci and those issues the overall concordance of multiple loci
    lengths take[s] care of any worry about sequence variation falsely including
    someone.
    “Q. You, yourself[,] I think accepted the proposition that if
    someone is consistent across several alleles, but inconsistent in one, your
    conclusion is that they‟re excluded as a possible source, right?
    “A. I‟m one of those anything can happen [people]. As a purist,
    yes. On a practical level, that when I begin a case comparing one person
    against one sample, when you have entire profiles consistent, then the
    chance that you‟re actually going to have exclusions as you‟re talking about
    is vastly true, they‟re highly reduced. [¶] And also this is what our
    population statisticians count in because in creating data bases all of those
    people who had, for example, a 16 allele in the data base may have had
    different sequences. So what we are doing is we are saying, [„]here is the
    frequency of people with this length trait regardless of this sequence.[‟] [¶]
    So this is why specifically over the course of the entire 13 locus profile this
    is not a great concern.
    “Q.    It‟s a concern to the person who is wrongfully included, is it
    not?
    “[PROSECUTOR]: Objection. Argumentative.
    69.
    “THE COURT: Sustained.
    “Q. You said yourself that if [defendant] and I shared a different
    sequence at [a] locus you would exclude based on that difference. [¶] Do
    you recall this question?
    “A. Almost definitely would have been excluded. Excluded by
    other loci also.
    “Q.    That‟s an assumption you‟re making, right?
    “A.    It‟s a pretty good assumption.
    “Q. That‟s based on your assumption that you wouldn‟t see
    concordance between multi[ple] loci and just one where it doesn‟t match?
    “A. It‟s based on the knowledge that when you are using 13 STR
    loci the chances of a random one grabbing two individuals and the[m]
    having the same profile is just exceedingly rare.”
    Myers explained that a 13-loci match is exceedingly rare even though it might be
    expected to eventually occur in the billions of comparisons that can be performed within
    a massive database of millions of people. A match in that context is different.
    Myers agreed that Butler 2005 lists alleles at various loci that have been found to
    have the same length but different sequence. These are different alleles, but they are not
    distinguishable by the STR procedure. Myers‟s STR analysis did not attempt to
    distinguish the sequence of any of the alleles, and he agreed that if defendant‟s alleles
    contained different sequences, “he would still be included based on the lengths, but under
    the incredible unlikely event that someone would match at all of the lengths and still have
    different sequences than the evidence [sample], yes, he would be an exclusion.” Myers
    stated that allele length was the focus of most forensic labs because a “huge practical
    limitation” prevented them from sequencing. If they sequenced, they would complete
    only a few cases per year.
    70.
    g.     Statistics*
    Myers generated a report based on his mixture interpretation, including a statistic
    stating the chance that a randomly chosen person in the population would have the
    genetic profile of the mixture‟s major contributor. He used databases of allelic
    frequencies to estimate how frequently a particular profile would appear in the
    population. And he used the formula from the NRCII report with a modification referred
    to as theta.
    On cross-examination, Myers explained that he used Caucasian, African-
    American, and Hispanic databases to perform his statistical calculations. The databases
    consisted of about 200 people each. Defense counsel asked if the databases had been
    tested for independence expectations, as recommended by the SWGDAM (Scientific
    Working Group on DNA Analysis Methods) Revised Validation Guidelines (Forensic
    Sciences Communications (July 2004) vol. 6, No. 3), guideline 2.7. Myers answered that
    the databases had been tested as part of a paper by Budowle et al. published in the Journal
    of Forensic Sciences. The DOJ had not conducted any independence expectation tests on
    the databases. Myers explained that the guideline referred to tests that examine issues
    such as Hardy-Weinberg equilibrium,35 to compare the observed data versus the expected
    data in a database. Myers was aware of the criticism of the FBI‟s independence testing as
    insufficient to test for potential departures from Hardy-Weinberg equilibrium, but
    Budowle responded to the criticism and Myers agreed with his position.
    *      See footnote, ante, page 1.
    35     Hardy-Weinberg equilibrium refers to the frequencies of alleles and genotypes
    within a population.
    71.
    h.     Reference Blood Samples*
    In May 2005, Myers began analyzing the reference blood samples collected from
    Amber and defendant. Myers received these samples from Agent Smith. Myers had two
    reference samples for defendant—one from 1989 and one from 2005. Because the
    reference samples were blood samples, they did not require the differential DNA
    extraction needed to separate the sperm and epithelial cells. Myers lysed the cells and
    extracted the DNA from the blood. As with the other samples, he quantitated the DNA,
    amplified it with the Profiler Plus and COfiler kits, and analyzed the PCR products with
    the 310 Analyzer and the computer software. Myers tested the three reference samples at
    the same time, in addition to the various controls. The controls tested as expected, and
    nothing in the results suggested the testing was not correct.
    From these results, Myers generated a genetic profile for both Amber and
    defendant. Amber‟s profile was consistent with having come from the same person as
    the epithelial cell fraction from the vaginal swab that Myers had tested months earlier.
    The profiles matched at all 13 loci. And all 13 loci of defendant‟s profile matched those
    of the major contributor from the vaginal swab‟s sperm cell fraction.
    According to the DOJ‟s routine practice, Myers ran every sample at least twice
    through the 310 Analyzer for reproducibility of the result. Myers applied stringent
    standards to determine whether a peak was an allele or an artifact. The reruns he
    performed in this case verified that he made the proper calls. He had confidence in the
    results.
    i.     Validation*
    Myers explained the validation procedures for a forensic typing system. The DOJ
    validated the STR protocol by following guidelines for validation of a new system prior
    *      See footnote, ante, page 1.
    *      See footnote, ante, page 1.
    72.
    to its use. The DOJ‟s validations went beyond that required by internal validation. Some
    of the DOJ‟s studies, including those for the validation of the Profiler Plus and COfiler
    kits, were consistent with developmental validation, and the results of those studies were
    ultimately presented at a scientific meeting.
    With the Profiler Plus and COfiler kits, the DOJ analysts made very few
    deviations from ABI‟s guidelines, and none that changed the fundamental procedure.
    Those changes were incorporated into the DOJ‟s written procedure. For example, the
    DOJ‟s interpretation guideline required a certain RFU as an absolute minimum, whereas
    ABI‟s guidelines allowed interpretation with caution below a certain level. Also, the
    DOJ performed “smoothing” of the data at a different level, which was recommended by
    ABI‟s employees for experienced analysts. In general, the DOJ analysts maintained a lot
    of contact with ABI. The DOJ analysts validated the smoothing level, but they already
    knew it was beneficial.
    As a part of the DOJ‟s accreditation, external reviewers examined the lab‟s
    validations and determined whether they were sufficient to justify the use of the test. The
    reviewers informed the DOJ if they believed the validation was insufficient.
    On cross-examination, Myers again addressed the deviations the DOJ had made
    for using the Profiler Plus and COfiler kits. First, the lab‟s interpretation guideline
    required an absolute minimum of 75 RFU, whereas ABI‟s guidelines allowed
    interpretation with caution below 150 RFU. Second, the lab lengthened the final
    extension of the PCR thermal cycling from 45 minutes to 90 minutes, based on validation
    experiments conducted in the lab that showed some PCR products were otherwise not
    copied to full length. This was especially the case when the reaction contained more than
    the optimum amount of DNA. The extra extension time on the final cycle allowed
    extension to finish and adenylation (addition of a final adenosine nucleotide) to occur.
    Third, the lab performed light smoothing of the data, rather than heavy smoothing. ABI‟s
    user manual recommended heavy smoothing, which resulted in more rounded, gradual
    73.
    peaks, rather than sharp, pointed peaks on the electropherogram. ABI‟s employees,
    however, recommended to Myers that more advanced analysts use light smoothing
    because those analysts could differentiate spurious peaks from others. The lab validated
    the light smoothing and determined it was a better method. Myers believed ABI‟s new
    user manual now recommended light smoothing.
    Myers reiterated that the DOJ conducted internal validation studies on the Profiler
    Plus and COfiler kits before they were used in casework. These studies did not include
    stutter percentages. Instead, the DOJ relied on ABI‟s work on stutter percentages. Myers
    agreed that stutter percentages had varied some in different studies, but the key for most
    labs was the determination of how conservative they wanted to be with their thresholds.
    j.     Proficiency Testing*
    Myers had undergone at least 20 proficiency tests for the STR procedure. The
    proficiency tests were both internal and external, although he was aware he was being
    tested. Myers explained that blind proficiency testing requires that no one in the lab,
    including the supervisors, know the testing is occurring. This type of testing is very
    difficult to implement. The DOJ lab had voluntarily participated in a feasibility study
    regarding implementation of blind proficiency testing many years prior to this hearing.
    The lab got the correct result in the test. The study, however, ultimately determined that
    blind proficiency testing would be very difficult to implement on a large scale.
    Myers explained that the DOJ was audited by the American Society of Crime
    Laboratory Directors Laboratory Accreditation Board (ASCLD/LAB) and also by the
    DNA Advisory Board Standards (also known as the FBI Standards) because the lab
    received federal funding as part of the database program. ASCLD/LAB accredited labs
    throughout the world, and its accreditation meant the lab was following its minimum
    standards in areas such as quality assurance, work validation, and training of personnel.
    *      See footnote, ante, page 1.
    74.
    Myers explained that the DOJ lab had successfully passed the audits by both boards. The
    lab had been accredited since 1993.
    On cross-examination, Myers agreed that accreditation does not guarantee good
    scientific work. But the ASCLD/LAB auditors thoroughly examined five cases from
    each analyst at the lab. Myers believed the auditors may have examined his work in this
    case the last time the lab was audited. According to an audit report, auditors examined
    50 forensic profiles that the lab had uploaded to the national index and found that two
    profiles were inappropriate. One was incomplete and one was inaccurate. Myers agreed
    that the accreditation process did not prevent instances of sample switching,
    contamination, or sloppy handling.
    k.     Quality Control*
    The DOJ lab‟s quality control included the use of various controls for the PCR
    process and for contamination. The DOJ‟s facility, protocols, and actual casework were
    reviewed and inspected by internal committees and by state and federal accreditation and
    reviewing agencies. Every time an analyst at the lab completed a case, the work
    underwent a highly detailed technical review. If the reviewer agreed with the analyst‟s
    results, the case was then administratively reviewed for proper documentation.
    On cross-examination, Myers testified that the lab had a quality control
    department that was responsible for checking the reagents and the kits used in the STR
    protocol. Myers explained that it was his practice to clean and decontaminate his lab
    bench counters by wiping them with water, alcohol, and a bleach solution. He never
    placed evidence directly on the counters; he always used a clean paper surface. Myers
    stated that the controls run in this case tested as expected.
    *      See footnote, ante, page 1.
    75.
    l.     Contamination*
    Myers noted that flexibility is required in the interpretation of samples that might
    have been exposed to unknown environmental conditions. Freshly drawn clinical
    samples do not require the same considerations. The packaging of the 1989 vaginal swab
    showed no indication that it was one of the swabs sent to the FBI, which Myers thought
    was an indication that fewer people had handled it. He noted that vaginal swabs, by their
    nature, are more difficult to contaminate than other types of samples.
    On cross-examination, Myers explained that instances of contamination connected
    to a particular analyst at a particular moment had no bearing on other analyses in the lab.
    If, however, the contamination was of a reagent used by more than one analyst, the
    contamination could affect several cases. The lab‟s quality control department was
    supposed to catch these instances of contamination. Myers believed the lab had never
    experienced an outbreak of widespread contamination.
    Defense counsel presented Myers with several reports of contamination at the DOJ
    lab, none of which involved any of Myers‟s own work. Two reports in September 2004
    involved switched samples, not contamination. Others involved contamination from
    another sample or from the analyst herself. In each report, it appeared that only the
    particular case had been affected by the contamination.
    On redirect examination, Myers reiterated that none of these contamination reports
    appeared to involve an outbreak of widespread contamination. Myers was not the analyst
    in any of those cases. He explained that the controls in each analysis and the lab‟s quality
    assurance program led to the capture of these instances of contamination and in the
    resulting reports being produced. The program had done what it was intended to do.
    *      See footnote, ante, page 1.
    76.
    2.      George Frank Sensabaugh, Jr.’s Testimony
    a.     Introduction
    George Sensabaugh was a professor of Biomedical, Environmental, and Forensic
    Sciences at University of California at Berkeley. He taught various courses involving
    DNA technology and had published many papers. He had been on the editorial board of
    the Journal of Forensic Sciences for many years, had served on both National Research
    Council committees, NRCI and NRCII, and had testified as an expert in approximately
    50 cases.36
    Sensabaugh believed the DOJ lab‟s STR protocols were “very sound” and
    generally accepted as reliable. The protocols complied with correct scientific procedure.
    He reviewed Myers‟s bench notes in this case and believed Myers‟s work was “done in a
    very sound way.” He called it “[g]ood solid science.” He said the method Myers used
    would yield scientifically reliable results.
    b.     Sperm*
    Sensabaugh explained that Myers‟s notes stated he observed an average of about
    60 sperm per 400x microscopic field with 50 fields. According to Sensabaugh, this was a
    “pretty good amount of sperm.” He explained that this high amount of sperm was not
    consistent with contamination: “It would be hard to conceive a contamination situation
    in which that number of sperm would be detected. If one is detecting those, that number
    of sperm on a swab[,] one would pretty much have to think that the swab [was] either
    immersed in a dilution of semen or a wet swab was wiped over a semen stain. Something
    of that sort.” He considered “an inadvertent transfer to be very unlikely given those
    sperm, that number of sperm.”
    36    Sensabaugh testified in this case as an expert in forensic DNA technology and
    molecular biology.
    *      See footnote, ante, page 1.
    77.
    c.     Vaginal Swab*
    On cross-examination, Sensabaugh outlined the correct scientific procedure for
    determining whether semen is present on a vaginal swab. First, a portion of the swab is
    extracted in saline or TRIS buffered solution. A small portion of that solution is put on a
    slide and stained with “Christmas tree” stain, which stains sperm heads and tails different
    colors. The sperm are then examined under a microscope and counted per microscopic
    field. The extent of bacterial contamination and the presence of epithelial cells (usually
    vaginal) can be observed. If no sperm are observed, an acid phosphatase or P30 test can
    be performed to determine the presence of semen. A negative P30 test indicates either
    that no semen is present or that the threshold is below the level of detection.
    Sensabaugh reviewed Frausto-Heredia‟s June 20, 1989 letter to the FBI lab. In it,
    she stated she was submitting three of the four vaginal swabs to the FBI. She stated she
    had tested the fourth one with the following results: “(+) Acid Phosphatase, (-) P30
    Rocket, NR on Enzyme Analysis, did detect foreign antigen[.]” Sensabaugh explained
    that the positive acid phosphatase result indicated the presence of an enzyme that is found
    at very high levels in semen. Sensabaugh did not know what threshold Frausto-Heredia
    used, but he assumed she diluted the semen in the range of one in 100 to one in 1,000.
    Sensabaugh explained that the rocket electrophoresis method is one of the less sensitive
    and more problematic P30 tests, and it is possible that semen was present below the test‟s
    level of detectibility. He assumed the “NR” meant no result on the enzyme assay, and he
    assumed the test was PGM typing. If the semen sample had been diluted, or if a
    substantial amount of the semen was no longer present in the vagina, PGM typing would
    be problematic. Further, PGM degrades in the vaginal environment, and possibly an
    insufficient amount was recovered from the swab. Frausto-Heredia did not identify the
    foreign antigen she detected, but Sensabaugh assumed she was referring to ABO activity.
    *      See footnote, ante, page 1.
    78.
    This information did not tell Sensabaugh very much about the quantity of semen
    on the swab. Sensabaugh noted that the material on dried vaginal swabs is quite stable
    for a number of years. He believed there was a moderate amount of semen on the swab,
    but he explained that the number of sperm was more pertinent because it contains the
    DNA. Frausto-Heredia stated she found 30 to 40 sperm on the slide, but Sensabaugh did
    not know if she was relating that to a field or the entire slide. Sperm per field was the
    usual way of reporting the number of sperm found. Sensabaugh noted that sperm could
    survive in the vagina for up to about 72 hours.
    d.     Amplification and Averaging*
    On cross-examination, Sensabaugh explained that the DOJ‟s protocol followed
    correct scientific procedures, and the “basic protocol that was employed, the methods
    used for amplification, the methods used for the analysis, the amplification products, all
    of that was according to the standard protocols.”
    Sensabaugh noted that both positive and negative controls were incorporated into
    the protocol. The negative controls and the reagent blank controls were indicators that
    there had been no contamination, which is a concern with PCR. The positive control
    indicated the procedures worked as expected. A quality assurance sample with a
    preestablished profile was also included. These controls enhanced the reliability of the
    testing and provided confidence in the results.
    According to Sensabaugh, Myers‟s STR analysis of both the epithelial and sperm
    cell fractions used more than a sufficient quantity of DNA to perform the analysis. After
    Myers‟s first amplification of the DNA, he reamplified with a few more cycles to try to
    get more product to bring up weak peaks that might have been at the threshold value in
    the first amplification. This was routine scientific procedure.
    *      See footnote, ante, page 1.
    79.
    Sensabaugh also explained it was good scientific procedure for Myers to perform
    replicates and average the results of those replicates, even though the lab‟s protocol did
    not mention these steps. A protocol provides the basic outline and framework of the
    analytical procedure, but it is not limiting. Rather, it is a baseline from which the analyst
    works. A protocol should not prohibit things ordinarily done in the course of scientific
    work. When an analyst encounters a situation that requires something extra to be done, it
    is good science to do that extra thing. A guideline “does not constrain one from
    thinking.”
    Sensabaugh explained that the electropherograms in this case demonstrated that
    the sperm fraction contained more than two peaks at some of the loci, indicating the
    presence of a mixture. To determine the extent of variation, Myers repeated the
    amplifications and injections, and averaged the results. The lab‟s protocol did not require
    this, but it was good science to try to get the clearest and most reproducible answer on the
    composition of mixtures. Sensabaugh had seen other analysts average results.
    Sensabaugh explained that averaging takes into account experimental variation
    that always occurs, providing a more accurate estimate of the true value than any single
    measurement. Thus, when multiple measurements have been made, the better technique
    is to determine both the average and the variance to get the best estimate of the true value
    and the precision of the measurements. If the variance is very large, the average of the
    measurements is not very accurate and there may be a problem with the measurements,
    whereas consistent results across multiple replications give the analyst confidence that
    the result is sound. Looking at each independent analysis separately does not provide the
    same level of confidence that the results are consistent.
    Sensabaugh reviewed each of Myers‟s eight runs independently to assess whether
    any different result would be obtained with any one of the runs, and he determined that
    the eight individual runs gave essentially the same results as the average of those runs,
    80.
    but averaging provided the best assessment of the true value. Averaging was the
    appropriate thing to do.
    Responding to defense counsel‟s repeated suggestions that Sensabaugh‟s research
    experience had no application to forensic science, Sensabaugh explained: “The contexts
    [of a research laboratory and a forensic laboratory] are different but the doing of good
    science is not different between the two. If one … wants to get the best estimate of a
    measurement then the best way to approach it, and this is very standard scientific
    protocol, as well as forensic protocol, is to make multiple determinations and then to
    average the values across those determinations.”
    Sensabaugh explained the two-fold significance of Myers‟s having tested the
    vaginal swab a month before the reference samples. First, defendant‟s reference sample
    could not possibly have contaminated the evidence sample (vaginal swab). Second,
    Myers had no prior knowledge of the reference types and could not have been influenced
    by a subjective assessment of trying to fit the data to the reference samples.
    e.     Mixture Interpretation*
    Sensabaugh reviewed Myers‟s mixture interpretation notes and concluded that
    Myers relied on sound scientific principles and “took a sound approach” to interpreting
    the mixture. The minor peaks in the mixture tracked with the epithelial cell type that was
    presumed to originate from the female in the case. There was some overlap in alleles
    between the epithelial cell fraction and the sperm cell fraction, which is not uncommon in
    sexual assault evidence, and Myers‟s approach was an effort to make certain that the
    mixture was properly interpreted. In his statistical calculations, Myers used the basic
    formulas recommended by the NRCII report, incorporating the correction for population
    structure. These formulas were generally accepted. Overall, looking at Myers‟s bench
    *      See footnote, ante, page 1.
    81.
    work and statistical calculations in this case, Sensabaugh believed Myers followed proper
    procedures and obtained scientifically sound results.
    On cross-examination, Sensabaugh stated that the results were entirely
    interpretable as a mixture of two contributors, one of which was the female from whom
    the sample was collected. This conclusion was based on a comparison with the epithelial
    cell fraction, which yielded a genetic profile that was seen at a low concentration in the
    sperm cell fraction. Sensabaugh examined the peak heights at each loci and determined
    that Myers‟s opinions of major and minor contributors were justified. Sensabaugh
    explained that Myers entered the data, then used software to apply the NRCII formulas
    and perform the calculations for the frequency of the profile in three major ethnic
    populations. Sensabaugh verified that the algorithm used by the lab was the correct
    computational format.
    f.     Same Length but Different Sequence Alleles
    Sensabaugh stated that he believed sequencing of STR alleles was rarely, if ever,
    done. The probability that two genetically different people would match at 13 STR loci
    is almost infinitesimal. And sequencing is not an efficient method. The payoff is much
    greater by testing additional STR loci.
    On cross-examination, Sensabaugh explained that it was well known in the field of
    human genetics that, among people, some STR alleles contain different sequences even
    though they are the same length. Sensabaugh was aware that several alleles used in STR
    analysis had been found to show this sequence variation. STR analysis, however, is
    based only on allele length, not sequence. The concept of sequence variation had been
    studied for a long time, beginning in the days of RFLP testing, which also compared
    DNA fragments by length rather than sequence. Sensabaugh agreed that if two samples
    have different sequences at the same locus, then the DNA samples come from two
    different people. And he agreed that if even one of defendant‟s alleles was found to be a
    82.
    different sequence than the perpetrator‟s matching allele, then defendant would be
    excluded as the perpetrator.37
    According to Sensabaugh, it was nevertheless correct scientific procedure to
    compare alleles by length without taking into account possible sequence differences
    “because the statistic that one is using to assess frequency of occurrence is based solely
    upon the length. And any sequence variants that may be included within an allele of a
    particular length are all included within that particular statistic.” But again he agreed that
    if sequencing revealed that defendant possessed a variant allele, he would be excluded as
    a source of the sperm sample.
    Sensabaugh explained that STR analysis is more efficient than sequencing for
    identifying a person to the exclusion of all others. The objective of STR analysis is to
    test a large number of loci (13 at that time) such that the frequency of occurrence of the
    profile is infinitesimally small. And while sequencing might occasionally exclude
    someone, “the chances are that if a person is different that way [in sequence,] they will
    also be different [in length] at one of the STR loci.” Furthermore, based on the rate for
    single nucleotide mutations (the substitution of one base for another), most sequence
    variants are relatively uncommon.
    g.      Error Rate*
    Sensabaugh explained that both he and the NRCII report concluded that a lab error
    rate should be considered separately from the genotype frequency. Sensabaugh endorsed
    the notion of introducing evidence of an industry-wide lab error rate at trial and then
    allowing the particular lab to explain why the error rate does not apply to that lab. A lot
    37     Sensabaugh noted that only the STR portions, not the entire genome, would need
    to be sequenced. Current science was capable of doing this. DNA sequencing was done
    on a daily basis by scientists all over the world. In fact, entire genomes had been
    sequenced.
    *      See footnote, ante, page 1.
    83.
    of scientists in the field preferred not to introduce error rates at all. Sensabaugh believed
    that labs with errors in their proficiency testing should be required to explain what they
    have done to correct their problems. He believed it was fair to ask an analyst if he had
    ever made a proficiency error. Accredited labs were required to keep records of their
    analysts‟ proficiency records.
    On cross-examination, Sensabaugh stated the consensus was that an error rate
    should be introduced on a case-by-case basis because there was no meaningful way to
    attach an error rate to any single statistical estimate of genotype frequency. If an
    industry-wide error rate exists, that is probative and should be introduced. And if a lab
    takes precautions against foreseeable errors, that should also be introduced. A lab should
    be allowed to present evidence of its own proficiency work and precautions against error.
    Consistency across multiple determinations reduces the chance that a single
    determination was made in error. Sensabaugh believed an error rate above one or
    two percent was unacceptable, and any lab contributing disproportionately to the overall
    lab error rate should go offline to correct its problems. Sensabaugh explained that in
    evaluating any evidence, the chance that a mistake or error was made must be assessed.
    Sensabaugh agreed that an analyst could discuss his individual proficiency testing results
    as some indication of his individual error rate. When defense counsel asked if this would
    create the implication that a finite number of proficiency tests accurately estimates an
    error rate, Sensabaugh answered:
    “Well, that‟s the problem with presenting error rates in general.
    [T]here are a number of problems with how you define it. An industry
    standard error rate based upon proficiency trials. Proficiency trials are truly
    artificial situations. One should not make mistakes on them, obviously,
    because they are artificial situations. [¶] … [¶] It would take a very large
    number of proficiency tests [to compute an analyst‟s error rate], but the
    other part of it is that every case has it[s] unique features. And so how do
    you assess an error rate when you have an old vaginal swab compared to a
    fresh vaginal swab? How do you compare an error rate when you have an
    old blood stain compared to a fresh blood stain? How do you compare the
    84.
    error rate when you have a blood stain that is on a windowsill as opposed to
    one that is on a rug? All of these circumstances … are encountered in
    ordinary forensic practice. And it would be very difficult to provide—to
    replicate all of them as part of a proficiency trial.”
    Sensabaugh believed an analyst should go no further than to say that he or she had taken
    a certain number of proficiency tests and thus far had made no errors. This would not
    translate into an error rate of zero. Sensabaugh believed the better line of questioning
    would be to look at the particular elements of a case and question at what point error was
    possible.
    Sensabaugh explained that after the 1996 NRCII report, error rates were no longer
    a major issue in the field at large, but some people continued to raise questions about
    them. The difficulty of conducting blind proficiency trials had been demonstrated.
    Whenever they were attempted, the labs would recognize them. Because broader
    proficiency testing programs were well-established and the results available, the need for
    incorporating error rates into the statistic had diminished. Some people thought NRCII
    was wrong, but Sensabaugh felt those people mistakenly believed proficiency testing
    could be incorporated into a forensic lab in a production-line basis, as it is in a clinical
    lab. In fact, that sort of redundancy is built into a forensic case.
    h.     Statistics*
    On cross-examination, Sensabaugh explained that a considerable dispute arose
    after the 1992 NRCI report regarding the way the report dealt with population genetics
    and statistical issues. In 1994, Eric Lander from the NRCI committee and Bruce
    Budowle of the FBI wrote a letter, published in the journal Nature, stating that they
    believed the main population and statistical issues had been resolved, even if some
    peripheral issues remained. A number of prominent people responded to the letter,
    *      See footnote, ante, page 1.
    85.
    stating that the population figures were not good and that accurate estimates of lab error
    rates were needed.
    On direct examination, Sensabaugh stated that the letters were written in 1994,
    before the 1996 NRCII report. The 12-person NRCII committee, of which Sensabaugh
    was a member, considered the same issues raised by the letters. In fact, these issues were
    part of the reason the NRCII committee was created. The committee concluded that the
    error rate should be a separate consideration from the population statistic.
    As for controversy over whether hidden levels of population structure might
    distort statistics, by the time NRCII was deliberating, there was a considerably larger
    body of population data suggesting that there was no significant distortion and that
    correction would compensate for the distortion that did exist.
    3.     Delia Frausto-Heredia’s Testimony—for the Defense*
    In June 1989, Delia Frausto-Heredia was employed by the California DOJ crime
    lab in Fresno. She worked on this case with Gary Cortner and a third analyst. When she
    received the case, Cortner had already made slides from the vaginal swabs and found
    sperm on the slides. Cortner‟s notes stated that he observed about 20 to 25 sperm (some
    were just heads) on a slide. Two photographs attached to the same page of Cortner‟s
    notes showed a single intact sperm on each. Frausto-Heredia explained that the
    photographs did not show everything Cortner observed; they were simply to illustrate
    what he found.
    Frausto-Heredia‟s task was to examine the vaginal and penile swabs and
    defendant‟s underwear for the presence of semen. She examined the swabs and
    underwear at different times, as was her practice to avoid contamination. The vaginal
    swabs and clothing were stored in different locations—the vaginal swabs in the
    refrigerator portion of the evidence vault and the clothing in the freezer.
    *      See footnote, ante, page 1.
    86.
    On June 12, Frausto-Heredia examined the vaginal and penile swabs. First, she
    removed the victim sexual assault kit from the refrigerator portion of the evidence vault.
    The four vaginal swabs were together in one envelope. She tested one swab for acid
    phosphatase and got a positive result. She explained that acid phosphatase is present in
    high levels in seminal fluid and in low levels in other body fluids, such as vaginal
    secretions. A positive acid phosphatase test is presumptive for semen. Frausto-Heredia
    also tested the swab for the presence of the P30 protein, also presumptive for semen, but
    got a negative result. Frausto-Heredia also tested the swab for PGM, another highly
    unstable protein found in seminal fluid. She was not surprised to get no results. She
    explained that these three unstable proteins degrade quickly. They begin degrading
    immediately inside a deceased victim, and they degrade quickly when the sample is not
    stored properly, such as when the sample is not air dried or not stored in a paper bag.
    Sperm cells, by contrast, are extremely stable.
    Frausto-Heredia could not estimate the number of sperm that would be collected
    12 hours after ejaculation. She explained there were too many variables, including how
    much of the sample was collected. For example, nurses tended to collect more of the
    sample pooled in the cervix, whereas coroners tended to collect less by swabbing the
    vagina. In a deceased victim, the seminal fluid immediately begins to degrade, whereas
    the sperm does not degrade quickly. In her cases, Frausto-Heredia had observed between
    zero and hundreds of sperm per slide.
    After Frausto-Heredia examined the vaginal swabs, she returned them to the
    victim sexual assault kit and placed the kit back in the refrigerator portion of the evidence
    vault.
    At this point, Frausto-Heredia replaced the paper cover on her work surface. Then
    she removed the suspect sexual assault kit from the refrigerator portion of the evidence
    vault and tested defendant‟s penile swab for acid phosphatase. The result was negative.
    87.
    A week later, on June 19, Frausto-Heredia examined defendant‟s underwear. The
    only test she performed on defendant‟s underwear was the acid phosphatase test, which
    was negative. Nothing suggested that seminal fluid was present on the underwear. She
    found some stains that fluoresced under the laser, but they may have been urine. Frausto-
    Heredia was quite certain there was no seminal fluid on defendant‟s clothing. The penile
    swab was also negative for acid phosphatase. Frausto-Heredia explained that based on
    the time period and the manner in which the items were preserved, she would have
    expected a positive acid phosphatase result if seminal fluid were present, as it was on the
    vaginal swabs.
    After Frausto-Heredia examined the vaginal swabs, she gave them to O‟Clair.
    O‟Clair did not take possession of defendant‟s penile swab or underwear.
    On cross-examination, Frausto-Heredia again explained that the photographs of
    sperm on a slide in Cortner‟s notes showed only a portion of a slide. The photographs
    were merely representative of what was on the slides.
    The results Frausto-Heredia obtained on the acid phosphatase, P30, and PGM tests
    were not inconsistent with the presence of sperm on the slide because these three
    components are all very unstable compared to sperm. Frausto-Heredia had worked on
    many cases where she had gotten no results on these three tests, then years later found
    sperm that yielded DNA for profiling.
    4.     Trial Court’s Ruling*
    The parties submitted on the written briefs, and the trial court ruled as follows:
    “The Court finds that the evidence presented at the hearing through
    the two witnesses that were presented by the Prosecution[,] taking into
    consideration the testimony provided by the witness for the Defense, are
    sufficient that the evidence established that the PCR/STR DNA testing was
    done in this case in a proper fashion. It was performed by a qualified
    *      See footnote, ante, page 1.
    88.
    expert and it was … a sound application, a correct application of scientific
    procedures and it‟s generally accepted in the scientific community. And it
    resulted in correct scientific results.
    “I find in a majority of the—and that deals with like basically the
    other first prongs, and the second prong, and the third prong as set forth in
    Brown[, supra, 
    91 Cal.App.4th 623
    ] and Venegas[, supra, 
    18 Cal.4th 47
    ].
    And I find that the evidence should be permitted to go to the jury.
    “The correct scientific procedures were used in this particular case.
    There [are] some certain questions about whether or not there is some sort
    of contamination. There [are] some questions about handling of the
    documents. But as I indicated earlier in my prior rulings, that those go to
    the weight of the evidence, not to its admissibility.
    “You know, in doing—I realize this is a case where we have to do a
    case specific inquiry. In all of the evidence that we had that was presented
    by the Prosecution with really no defense evidence to the contrary other
    than the evidence that you could arguably say is contrary and the materials
    that were exhibits. Those, again, didn‟t convince me that there was
    anything that was improperly done. And that the correct scientific
    procedures were not used.…
    “And so, I could try and address some of these other things, you
    know, as to the thing and I‟m thinking it probably might be a good idea to
    do that. I think we‟ve already addressed the contamination issue. The lack
    of a blind proficiency testing. You know, I don‟t think that‟s, you know,
    that much of an issue, because the lab has undergone and passed
    proficiency testing.
    “And a failure to provide sequenc[ing]. Again, there‟s no evidence
    of failure to provide the sequenc[ing] is not generally accepted in the
    community. The failure to apply the FBI protocols and all. And again, in
    relationship to that, while not all the FBI protocols may have been followed
    in regards to the matter, the lab has still been certified and accredited by the
    ASCLD as having scientifically accepted … protocols and procedures. So
    that‟s sufficiently been done.
    “The big issue on the … population data base is basically the basis
    of this case being reversed on its last occasion. And argued again by the
    Defense here, the fact of, you know, that they say that the population data
    base science tests were inadequate. You know, they were adequate. The
    same data base that‟s being questioned in this case has been accepted in the
    case of People vs. Wilson[, supra, 
    38 Cal.4th 1237
    ] even though it excludes
    89.
    one data base in relationship to the Asians. So I think that issue has pretty
    much [been] taken care of.
    “You know, in this case, you know, Mr. Myers did follow the
    appropriate, you know, testing procedure as set forth in the Profiler Plus
    and the Cofile[r] PCR and STR kits. Those were used and they were, and
    those kits have been found acceptable in the general, you know, scientific
    community and there‟s case law of People vs. Henderson[, supra, 
    107 Cal.App.4th 769
    ] that addresses that. And the witness—even
    Dr. Sensabaugh said the averaging of the multiple runs was good [science]
    and procedures that were used were consistent with that protocol.
    “We‟ve already addressed the chain of custody issues as well. So
    the Court‟s going to allow the DNA testing. Of course you‟re going to be
    able to attack that by your own witnesses, you know, as to whether or not it
    is sufficient. But it doesn‟t go to its admissibility. Again, that all goes to
    its weight.
    “So that takes care of that.…”
    5.     Defendant’s Contentions
    a.     Blind Proficiency Testing*
    Defendant first argues that although the DOJ lab was accredited, it failed to
    conduct the blind proficiency testing required by generally accepted scientific
    procedures. Defendant states that the 1992 NRCI report “explicitly makes blind
    proficiency testing a necessary prerequisite to admission.”38
    The People respond that the more recent 1996 NRCII report demonstrates that the
    NRC does not require blind proficiency testing.
    Defendant replies: “NRC has specifically noted that blind proficiency testing is
    entirely different and indeed, „provides a truer test of functional proficiency because the
    *      See footnote, ante, page 1.
    38     Defendant quotes this portion of NRCI: “[C]ourts should require that a proponent
    of DNA typing evidence have appropriate accreditation—including demonstration of
    external, blind proficiency testing (as well as other accreditation that might be mandated
    by government or come to be generally accepted in the profession)—for its evidence to
    be admissible.” (NRCI, supra, at pp. 106-107.)
    90.
    analysts will not take extra care in analyzing samples.‟ ([NRCII, supra,] at p. 79.)” He
    states that, despite the difficulties in administering blind tests, “NRCII nonetheless
    recommends that „some of the tests should be blind.‟ ([NRCII, supra,] at p. 88.)”
    As the parties recognize, NRCII addresses not only the benefits of blind
    proficiency testing, but also the practical difficulties in administering it. Defendant is
    wrong that NRCII states blind proficiency testing “„provides a truer test of functional
    proficiency.‟” NRCII states instead: “It has been argued that full-blind testing provides
    a truer test of functional proficiency because the analysts will not take extra care in
    analyzing samples. Whether or not that is so, this form of proficiency-testing evaluates a
    broader aspect of laboratory operation, from the receipt of the „evidence‟ at the front desk
    through analysis and interpretation to final reporting.” (NRCII, supra, at p. 79, italics
    added.) As for the practical application of blind proficiency testing, NRCII
    acknowledges:
    “The logistics of full-blind proficiency-tests are formidable…. The
    TWGDAM [Technical Working Group on DNA Analysis Methods]
    guidelines recommend one full-blind proficiency test per laboratory per
    year if such a program can be implemented. The DNA Identification Act of
    1994 required that the director of the National Institute of Justice (NIJ)
    report to Congress on the feasibility of establishing a full-blind proficiency-
    testing program. The NIJ has reported that, although several of the large
    laboratory systems conduct blind testing in-house, there is no blind,
    external, DNA profi[ci]ency-testing program generally available to public
    or private laboratories. The report mentioned some potentially serious
    issues with blind testing, including the cost of implementation, the risk that
    DNA data from an innocent donor to the test might end up in criminal DNA
    databanks, and the chance that the test would impose excessive costs and
    time demands on law-enforcement agencies. The NIJ has contracted a
    study to review current testing programs and to examine alternative ways of
    performing blind tests.” (NRCII, supra, at pp. 79-80.)
    Furthermore, while NRCII does recommend that some of the proficiency tests
    should be blind, defendant‟s characterization of that recommendation is also misleading.
    NRCII‟s recommendation states:
    91.
    “Regular proficiency tests, both within a laboratory and by external
    examiners, are one of the best ways of ensuring high standards. To the
    extent that it is feasible, some of the tests should be blind.
    “Recommendation 3.2: Laboratories should participate
    regularly in proficiency tests, and the results should be available for
    court proceedings.” (NRCII, supra, at p. 88, italics added.)
    We conclude that the authority cited by defendant does not support the proposition
    that blind proficiency testing is required by generally accepted scientific procedures.
    And, as the trial court found, there was ample evidence that the DOJ lab was fully
    accredited and Myers‟s proficiency fully tested. Myers had undergone at least
    20 proficiency tests for the STR procedure alone. The DOJ lab had participated in a
    blind proficiency testing feasibility study in which the lab obtained the correct result, but
    which led to the conclusion that blind proficiency testing would be very difficult to
    implement on a large scale. Myers explained that because the DOJ lab was accredited by
    ASCLD/LAB (since 1993), it was required to adhere to certain standards of quality
    assurance, work validation, and personnel training.
    According to Sensabaugh, the difficulty with blind proficiency tests was that labs
    always recognized them. Broader proficiency testing programs were well-established
    and the results were available. He believed analysts should have to account for their
    proficiency errors.
    The trial court did not abuse its discretion when it determined that a lack of blind
    proficiency testing did not constitute incorrect scientific procedures.
    b.     Deviation from Protocol without Validation*
    Defendant contends the DOJ lab deviated from ABI‟s protocol in ways that had
    not been scientifically validated for reliability. Specifically, he points to the use of a
    different allele call threshold and a different level of data smoothing. He concedes that
    *      See footnote, ante, page 1.
    92.
    Myers testified the DOJ had validated its deviations, but says he failed to establish
    exactly how it had done so.
    At the Kelly hearing, the uncontroverted evidence established that the DOJ
    validated its STR protocol according to validation guidelines, and its studies were more
    extensive than what was required for internal validation. Some of its studies, including
    the validation of the Profiler Plus and COfiler kits, reached the level of developmental
    validation and were presented at a scientific meeting. In addition, the lab‟s validations
    were externally reviewed for sufficiency as part of the lab‟s accreditation. Furthermore,
    there was no evidence that the DOJ‟s allele call threshold was unreasonable or improper.
    Different labs adopted different thresholds, depending on how conservative they chose to
    be. As for data smoothing, the advisors at ABI personally recommended light smoothing
    for analysts with advanced experience. The DOJ validated the light smoothing level.
    Finally, Myers explained that none of the changes the DOJ made altered the fundamental
    procedure. In sum, there was substantial evidence from which the trial court could
    determine that the protocol followed by Myers was adequately validated. The court did
    not abuse its discretion.
    c.      Contamination*
    Defendant maintains that the prosecution failed to demonstrate through qualified
    experts that both law enforcement and the labs in this case used generally accepted
    methods for collecting, handling, and testing the vaginal swab. Defendant complains that
    the DNA on the swab was collected during Amber‟s autopsy in a mortuary and allowed
    to air dry. He claims that by the time the vaginal swab reached the lab in 2004, it “had
    repeatedly come into contact with [defendant‟s] biological samples, and his belongings.”
    He asserts that “the record affirmatively suggests that contamination had occurred.” He
    *      See footnote, ante, page 1.
    93.
    further argues that Myers‟s testimony failed to establish that he followed generally
    accepted methods to avoid contamination when he tested the DNA on the vaginal swab.
    We agree with the trial court that these issues fall outside of Kelly‟s third prong.
    As Venegas explained, “[s]hortcomings such as mislabeling, mixing the wrong
    ingredients, or failing to follow routine precautions against contamination may well be
    amenable to evaluation by jurors without the assistance of expert testimony.” (Venegas,
    supra, 18 Cal.4th at p. 81.)
    Contamination is a concept readily comprehensible to jurors for their evaluation
    and weighing at trial. (Venegas, 
    supra,
     18 Cal.4th at p. 81.) Thus, it is an issue going to
    weight, not admissibility, and the trial court did not abuse its discretion in so concluding.
    At trial, the jury was presented with ample evidence regarding the collection, handling,
    and testing of the vaginal swab, defendant‟s clothing, and other items, from which the
    jury could weigh the value of the resulting biological evidence.
    Moreover, we disagree with defendant that the Kelly record suggests
    contamination occurred at any stage in this case. Indeed, the evidence supported the
    contrary conclusion. Myers testified that the vaginal swab contained far too much sperm
    to have been transferred by contamination. He explained that dried vaginal swabs are not
    prone to contamination. He thought the defense‟s contamination scenario was unlikely in
    any lab, even one in the 1980‟s. He also explained the procedures he followed to
    eliminate or reveal contamination in the lab, on his own work bench, and in his PCR
    reactions. The controls he used in this case revealed no evidence of contamination. He
    explained that the reports of contamination presented by the defense were not connected
    with this case, his own work, or lab-wide contamination.
    Similarly, Sensabaugh testified that the large amount of sperm on the vaginal swab
    was not consistent with contamination. He could hardly imagine how contamination
    could transfer that amount of sperm and he considered an inadvertent transfer very
    unlikely. Sensabaugh explained that Myers could not have contaminated the vaginal
    94.
    swab with defendant‟s reference blood sample because he examined the blood a month
    after he examined the swab. And the controls Myers used in the PCR reactions
    established there had been no contamination in those reactions.
    Frausto-Heredia testified that she stored and examined the swabs and underwear
    separately to avoid contamination.
    d.      Averaging*
    Defendant complains that Myers‟s averaging of the STR results was “purely of his
    own invention,” not part of any written protocol for interpretation of data, and therefore
    not compliant with accepted scientific procedures. All of the evidence, however,
    supported the conclusion that averaging was correct scientific procedure.
    Myers explained that he performed the multiple amplifications and injections to
    ensure that the imbalanced peaks in the first amplification were not due to a rare
    stochastic occurrence. And, although there was no evidence of a written STR protocol
    calling for this averaging, the uncontradicted evidence established that it was simply
    good scientific procedure. Despite defense counsel‟s relentless attacks, Sensabaugh
    repeatedly explained that the averaging of multiple measurements is such a standard
    principle of scientific research and forensic protocol that it need not be written into a
    basic protocol. He explained that the best estimate of a true value is obtained by
    determining both the average and the variance of multiple measurements. Averaging was
    the correct thing for Myers to do.
    In any event, as Sensabaugh explained, in this case the variance between
    measurements was small and therefore each individual measurement would have
    supported the conclusion arrived at through averaging. In other words, averaging was the
    correct and appropriate method, but it did not affect the results in this case. The trial
    court did not abuse its discretion.
    *      See footnote, ante, page 1.
    95.
    e.     Triallelic Patterns*
    Defendant contends Myers refused to consider the possibility of a triallelic
    perpetrator, which would have excluded defendant as a contributor. He points to the
    trialellic pattern of the 23, 25, and 26 alleles at the FGA locus. Unfortunately, defendant
    cites no evidence to support his conclusion that Myers did not consider this possibility.
    In fact, for record authority, defendant cites his own posthearing brief, but no evidence
    from the hearing itself. Our reading of the record demonstrates instead that Myers was a
    well-trained and highly experienced analyst who was capable of considering the many
    facets involved in mixture interpretation, including whether a third peak most likely
    reflected a minor contributor in a mixture or a triallelic anomaly.
    Myers explained it was immediately clear that the sperm fraction was in fact a
    mixture. Indeed, the D21S11 locus showed four peaks in the sperm fraction. And
    because (1) the DNA source was a vaginal swab, (2) the difference between the
    contributors‟ peak heights was significant, and (3) the minor contributor‟s alleles
    matched those in the vaginal epithelial cell fraction, he assumed the minor contributor
    was Amber and he subtracted out her peaks, leaving the perpetrator‟s peaks. This
    procedure was in accord with the DOJ protocol.
    For example, although the sperm fraction showed three peaks at the D3S1358
    locus, Myers concluded that only two of the peaks belonged to the major contributor
    because the third peak was only about 20 percent of the shorter major peak. According to
    his notes, the average ratio of peak heights at that locus was 100 percent for the 14 allele,
    75 percent for the 15 allele, and only 16 percent for the 16 allele. In compliance with the
    DOJ protocol, Myers interpreted the much smaller peak as carryover from Amber‟s
    epithelial DNA, which contained 14 and 16 alleles.
    *      See footnote, ante, page 1.
    96.
    Similarly, at the FGA locus, Myers‟s notes state that the average ratio of the peak
    heights at that locus was 100 percent for the 26 allele, 93 percent for the 25 allele, and
    only 19 percent for the 23 allele. The epithelial DNA contained 23 and 26 alleles.
    We also note that the DOJ‟s written STR protocol addressed genetic anomalies,
    such as triallelism, as follows:
    “Peak height ratios lower than 70% may indicate a mixture,
    especially when seen at more than one locus. However, a single-source
    sample may also exhibit peak height ratios below 70%, especially when
    peak heights are less than 200 RFU. Analysts should consider results at all
    loci when interpreting samples that exhibit peak height ratios of less than
    70%. Depending upon the sample source, the loci in question, the number
    of loci affected and the percent disparity between allele peak heights, the
    sample may need to be re-amplified and typed. All loci should be
    evaluated in making this determination.
    “The following are also considerations in interpreting sample
    profiles: [¶] The presence of more than two alleles per locus, especially at
    more than one locus, may indicate a mixture. However, some individuals
    may exhibit more than two alleles at one locus due to genetic anomalies
    (e.g., trisomy, chromosomal translocation, mosaicism, and chimerism).”
    (Italics added.)
    We see no evidence that Myers neglected or refused to consider the possibility of
    triallelism in his interpretation. The trial court did not abuse its discretion.
    f.     DNA Sequence Variations
    Defendant raises two issues regarding variations in DNA sequence, both of which
    defense counsel vigorously pursued at the Kelly hearing: (1) alleles of the same length
    but different sequence and (2) peak height imbalance and allelic dropout. Defendant
    contends Myers‟s failure to investigate these issues constituted improper scientific
    procedure.
    As the evidence in this case established, most regions of DNA are the same
    between people. But mutations, such as the substitution of a single nucleotide for
    another, create sequence variations (nucleotide polymorphisms) even in fairly stable
    97.
    sequences. And, as Myers and Sensabaugh testified, a difference in sequence between
    two DNA samples demonstrates that the DNA samples come from two different
    people.39 The issues defendant raises here have to do with the ability of the STR system
    to cope with these sequence variations.
    1.     Introduction
    STR alleles are copied by PCR, and PCR relies on the binding of primers that have
    been designed to match the nearly universal sequences in the regions flanking the STR
    alleles. These flanking sequences are used as primer binding sites during PCR. With
    most people‟s DNA, the primers bind properly to the primer binding sites, and then the
    DNA between the primers is successfully copied. But if a person‟s DNA contains a
    mutation within a primer binding site, PCR‟s ability to amplify the allele may be affected.
    The fairly universal sequence is not present in the mutated primer binding site, and thus
    the now-mismatched primer does not bind properly to it. This can debilitate or even
    prevent amplification of the allele. Consequently, few or no copies of the allele are
    made, and the resulting allele peak is either small or nonexistent (null)—the result ranges
    from peak height imbalance to allelic dropout. When the allele drops out, which is the
    most dramatic consequence, a heterozygous genotype falsely appears to be a homozygous
    genotype at that locus because only one of the two alleles has been amplified.40
    39      Our discussion is also based on the assumption that two samples from the same
    person contain identical DNA, even when they originate from different cell types, such as
    sperm and blood. We do recognize that there are instances in which a mutation occurs in
    the DNA in one part of the body (e.g., sperm or cancerous tissue) but not in the DNA in
    another part of the same body (e.g., blood), and instances of other genetic phenomena,
    such as chimerism (e.g., due to the fusion of two fraternal twin zygotes into a single
    zygote); however, we imagine these to be fairly rare scenarios. (We also recognize that
    some mutations are heritable and might be found in family members, but we assume this
    is not relevant to most forensic comparisons between a perpetrator and suspect.)
    40   When null alleles are discovered, they are catalogued on the Short Tandem Repeat
    DNA Internet DataBase (STRBase) maintained by the National Institute of Standards and
    98.
    By contrast, when a person‟s DNA contains a mutation within the repeat motif of
    the STR allele itself, rather than the flanking regions, PCR‟s ability to amplify the allele
    is not affected. The primers bind to their binding sites, which are unaffected by the
    internal mutation, and the mutated stretch of DNA between the primers is copied,
    regardless of its sequence. Because the resulting amplified alleles are analyzed by length,
    not sequence, the sequence variation goes undetected by the STR procedure. The allele is
    considered a match to an allele of the same length, even though its sequence is actually
    different.41
    2.      Same Length but Different Sequence Alleles
    Defendant contends that because of the known existence of sequence variants
    within the STR alleles, his alleles should have been sequenced to determine if they
    matched the perpetrator‟s alleles in sequence, not just in length. He rejects the
    explanation that sequencing in forensic cases is impractical, and he asserts that a
    convenient procedure does not amount to a correct one.
    At the Kelly hearing, both Myers and Sensabaugh explained that the STR
    procedure cannot recognize a difference in sequence that might be contained within an
    allele because the STR procedure measures allele length, not allele sequence. And they
    both agreed that a difference in sequence would exclude defendant as the perpetrator.
    Technology and available at http://www.cstl.nist.gov/strbase under Null Alleles. See also
    Butler 2005, supra, at page 136.
    41      When sequence variants are discovered, they are also catalogued on the STRBase
    (http://www.cstl.nist.gov/strbase under Variant Allele Reports), which reports
    409 variants of the 13 core STR alleles, as of May 17, 2013. See also Butler, Advanced
    Topics in Forensic DNA Typing: Methodology (2011) (Butler 2011) appendix 1,
    pages 549 through 603.
    For a discussion on the general topic of sequence variation, see Butler, Forensic
    DNA Typing: Biology and Technology behind STR Markers (2001) (Butler 2001) at
    pages 89 through 93.
    99.
    Sequencing, however, is inefficient, has huge practical limitations, and is rarely done.
    They explained that STR testing for length alone is acceptable because of the extreme
    unlikelihood that a sequence variant would exist in a person whose alleles match in
    length at 13 STR loci. The chance of an STR match at 13 loci is infinitesimally small,
    and if a defendant‟s alleles do match in length at all 13 loci, it is highly unlikely that any
    of those alleles fail to match in sequence. If a person differs in sequence, he will likely
    differ in length at one or more loci. Furthermore, sequence variants are relatively
    uncommon.42
    We conclude that the trial court did not abuse its discretion in finding that Myers
    followed correct scientific procedure by using the STR procedure and not sequencing
    defendant‟s alleles to test for sequence variants. The evidence before the trial court
    established that although the STR procedure cannot discern sequence variants, its ability
    to discern length variants is extensive enough that a match at 13 loci is astronomically
    rare. The evidence therefore established it was extremely unlikely that defendant‟s
    alleles, which matched the perpetrator‟s alleles in length at 13 STR loci (the chances of
    which were infinitesimally small), would fail to match in sequence.
    42      Both Myers and Sensabaugh noted that allele sequence is similarly not considered
    in the statistical aspect of the STR procedure. Myers explained that statisticians rely on
    the length, not the sequence, of the STR alleles when they determine the frequencies of
    the alleles in the population. The resulting numbers define the frequency of people with a
    particular allele length, regardless of sequence. He explained that this is a reason that
    sequence variation is not a concern over the course of an entire 13-locus profile.
    Likewise, Sensabaugh testified that it is correct scientific procedure to compare allele
    lengths without accounting for possible sequence differences because the statistics used
    to estimate the frequency of the alleles are based solely upon length and any sequence
    variants are included in those statistics. This testimony explains that the STR statistical
    analysis (to determine allele frequencies) accounts for the fact that the STR procedure
    measures only allele length, and not sequence. But it does not address the match itself—
    whether a defendant‟s alleles actually match the perpetrator‟s alleles—which is the issue
    here.
    100.
    3.     Allelic Dropout and Null Alleles
    Defendant also contends that Myers failed to account for the possibility of allelic
    dropout and null alleles in the sperm fraction at the vWA locus where the results showed
    a small 16 peak and a large 17 peak. Myers interpreted these peaks as a homozygous
    17,17 genotype, which matched defendant‟s 17,17. Defendant suggests that the small
    16 peak might have been the result of a peak height imbalance caused by a mutation in
    the perpetrator‟s DNA that negatively affected amplification of the 16 allele, causing it to
    nearly drop out. Defendant argues that Myers should have followed published protocols
    to “recover” a possible null allele—such as lowering the annealing temperature or using
    degenerate primers43 (which we discuss below)—to determine whether the sperm
    fraction was in fact heterozygous 16,17, rather than what falsely appeared to be
    homozygous 17,17 due to allelic dropout.
    The People respond that defendant‟s argument suffers from a fatal flaw because
    Myers testified that using the same kit/primers on all the samples in the case eliminated
    any false results. The People paraphrase: “In other words, while a particular sample may
    produce a different result on a particular locus if two different kits were used to test that
    locus, this same problem would not occur if the same kit were used to test all the
    evidence (i.e., the vaginal swab and the reference samples) in a particular case.”44
    At the Kelly hearing, Myers testified that allelic dropout is fairly rare because the
    regions flanking the STR alleles are quite consistent among people. He was not
    concerned that a missed exclusion (i.e., a false match or inclusion) might occur because
    use of the same kit on everyone‟s DNA within a case ensures that no false results are
    produced. Myers explained that sometimes an analyst has a “good indication” that allelic
    43     Defendant cites Butler 2001, supra, at pages 90 through 93.
    44    The People cite Butler 2001, supra, at page 93 and Butler 2005, supra, at
    page 137.
    101.
    dropout has occurred due to peak height imbalance. In this case, there was no such
    indication, and the existence of a mixture with Amber‟s DNA explained the presence of
    the very imbalanced peaks in the perpetrator‟s sample.
    a.     The Theory
    Butler and other authors propound the theory that allelic dropout is not an issue in
    criminal cases when the same primers (and PCR conditions) are used on both the
    perpetrator‟s evidence sample and the defendant‟s reference sample—as long as the two
    samples come from the same person. While we agree with this theory, we believe it fails
    to consider and account for the possibility of an innocent defendant, as we will explain.
    We begin with some statements of this theory. Butler explains in Butler 2001, in
    Butler 2005, and also in his 2009 book, Fundamentals of Forensic DNA Typing (Butler
    2009):
    “No primer set is completely immune to the phenomenon of null
    alleles. However, when identical primer sets are used to amplify evidence
    samples and suspect reference samples, full concordance is expected from
    biological materials originating from a common source. If the DNA
    templates and PCR conditions are identical between two samples from the
    same individual, then identical DNA profiles should result regardless of
    how well or poorly the PCR primers amplify the DNA template.” (Butler
    2009, supra, at p. 223, italics added; see also Butler 2005, supra, at p. 137
    & Butler 2001, supra, at p. 93.)
    Butler also explains in a recent article:
    “Although usually rare (≈0.1%), primer-binding-site mutations can
    give rise to typing results that do not reflect the true underlying alleles
    present in a DNA sample. Most university and forensic labs conduct
    population genetic research or casework with only a single STR typing kit.
    Therefore, investigators do not typically have the opportunity to cross-
    check results with different PCR primer pairs. It is worth noting that, by
    using consistent primers within a laboratory, question and known samples
    will agree if both contain the same primer-binding-site mutation. In other
    words, false homozygotes caused by allele dropout in a heterozygote when
    a primer fails to anneal properly and extend are not a problem within a
    laboratory. It is with interlaboratory comparisons and DNA databases
    102.
    supplied with results from multiple laboratories using different kits where
    potential null alleles can cause artificial mismatches.” (Butler, et al.,
    Variability of New STR Loci and Kits in US Population Groups (2012)
    available at http://www.promega.com/resources/articles/profiles-in-
    dna/2012/variability-of-new-str-loci-and-kits-in-us-population-groups, as of
    May 17, 2013, italics added, fns. omitted.)
    Another source states:
    “In processing casework, samples typically are amplified using the same kit
    or primer set. Thus, any primer mismatch present in the [defendant‟s]
    reference sample would also be present in an evidence sample that
    originated from the same individual.” (Leibelt et al., Identification of a
    D8S1179 primer binding site mutation and the validation of a primer
    designed to recover null alleles (2003) 133 Forensic Science International
    220, 225, italics added.)
    Another says:
    “Null alleles are STR alleles that, possibly because of a mutation in
    the primer [binding] sequence, are not amplified by PCR. A null allele can
    cause an individual who is truly heterozygous to be wrongly recorded as
    homozygous for the allele that is amplified. Individual null alleles are
    difficult to detect, but a high prevalence of null alleles at a locus may be
    detected via excess homozygosity [citation]. See Butler [2001] for the
    approaches used to minimize this problem, which is now rare with modern
    STR typing techniques.
    “Null alleles cause no problem for DNA profile interpretation
    provided that each null allele is consistently unamplified in repeat PCR
    assays. In that case, crime-scene and defendant profiles will correctly be
    recorded as matching if the defendant is the true source of the crime-scene
    DNA. This might be expected to occur if both crime scene and defendant
    samples were profiled in the same laboratory. Otherwise, differences in
    protocol, or use of PCR kits from different manufacturers, could generate a
    null allele in one laboratory that is non-null in another lab.” (Balding,
    Weight-of-Evidence for Forensic Profiles (2005) p. 47, italics added.)
    Finally, authors David Kaye and George Sensabaugh, the latter of whom testified
    in this case, state:
    “[M]utations in the region of a primer can prevent the amplification of the
    allele downstream of the primer (null alleles). [¶] … [¶] A null allele will
    not lead to a false exclusion if the two DNA samples from the same
    103.
    individual are amplified with the same primer system, but it could lead to
    an exclusion at one locus when searching a database of STR profiles if the
    database profile was determined with a different PCR kit than the one used
    to analyze the crime scene DNA.” (Kaye and Sensabaugh, Modern
    Scientific Evidence: The Law and Science of Expert Testimony, Scientific
    principles—How is DNA extracted and amplified? (2012) § 31:41 & fn. 2,
    italics added.)45
    b.     When the Defendant is Guilty
    We agree that allelic dropout does not appear to be an issue when the defendant is
    in fact the perpetrator. When the defendant is guilty, the evidence sample from the
    perpetrator (collected at the crime scene) and the reference sample from the defendant
    (collected later from the defendant to compare to the perpetrator‟s sample) originate from
    the same person and thus contain identical DNA. The two resulting profiles will be the
    same because the same template DNA is amplified with the same primers under the same
    conditions, and any allelic dropout that occurs due to any mutations in the template will
    occur identically in the two identical samples. Thus, the profiles will match, even if
    allelic dropout occurs, because the DNA in both samples is the same. Accordingly,
    allelic dropout will not lead to the false exoneration of a guilty defendant.
    In a graphical representation of this scenario, we refer to both samples (the
    perpetrator‟s evidentiary sample found at the crime scene and the defendant‟s reference
    sample) as “perpetrator/defendant” (or “perp./def.”) to emphasize that the perpetrator and
    the defendant are the same person. In this hypothetical, the genotype of the
    perpetrator/defendant is 14,19*, where 19* represents an allele that will not amplify
    because of a mutation in the primer binding site. The two identical DNA samples (from
    45      Footnote * to this article states: “This chapter is abridged and adapted from the
    Federal Judicial Center, Reference Manual on Scientific Evidence (3d ed. 2011), with
    updates and commentary for 2012 provided by John Butler, Ph.D., of the National
    Institute of Standards and Technology.” (Kaye and Sensabaugh, Modern Scientific
    Evidence: The Law and Science of Expert Testimony, Scientific principles—How is
    DNA extracted and amplified?, supra, § 31:41.)
    104.
    the same person) both experience the same allelic dropout. And although the profiles
    both falsely appear homozygous 14,14 due to the dropout, they are inaccurate in the same
    way. Thus, the match is true, and the perpetrator/defendant is correctly incriminated:
    allelic dropout
    perp./def.    14,19*                          false   14,14
    true match
    allelic dropout
    perp./def.    14,19*                          false   14,14
    And of course if no null allele is involved, for example, where the
    perpetrator/defendant is 14,19, and 19 represents a normal allele that will amplify and not
    drop out, the two identical samples will experience no allelic dropout. Both profiles will
    be true heterozygous 14,19 genotypes. The profiles are accurate, they match, and the
    perpetrator/defendant is correctly incriminated:
    no allelic dropout
    perp./def.    14,19                            true   14,19
    true match
    no allelic dropout
    perp./def.    14,19                            true   14,19
    Accordingly, the theory propounded by Butler and others appears to be correct as
    far as it goes, which it seems to us is only as far as a guilty defendant.
    c.      When the Defendant is Innocent
    But in cases where the defendant is not the perpetrator, the evidence sample from
    the perpetrator and the reference sample from the defendant originate from different
    people (because the defendant did not commit the crime and did not leave his DNA at the
    crime scene) and thus the samples contain different DNA. One sample may contain DNA
    with a mutation and the other sample may not. Allelic dropout may occur in one sample
    and not the other. Under these circumstances, allelic dropout in one sample may lead to a
    105.
    false match that falsely incriminates an innocent defendant. It is this possibility,
    represented below, that addresses defendant‟s concern that the perpetrator in this case
    might actually have been heterozygous, but falsely appeared homozygous due to allelic
    dropout, and therefore falsely matched defendant‟s homozygous genotype.
    If, as in the first scenario, the perpetrator is 14,19*, his mutant 19* allele will not
    amplify. The 19* allele drops out and his genotype falsely appears as a homozygous
    14,14. But if now the defendant (who is a different person) is a true homozygous 14,14,
    he will be considered a match to the perpetrator‟s false homozygous 14,14. The
    defendant is included as a possible perpetrator, and he is falsely incriminated:
    allelic dropout
    perp.    14,19*                           false    14,14
    false match
    no allelic dropout
    def.     14,14                            true    14,14
    We have not found reference to this scenario in the literature, but it plainly
    suggests that allelic dropout is not always a benign phenomenon in criminal cases
    because not all defendants are guilty. Where the perpetrator and the defendant are
    different people and where one of them is mutant heterozygous and the other is normal
    homozygous, the dropout in the mutant heterozygous sample can cause a false
    homozygosity and a false match to the homozygous sample. This means, in theory at
    least, that allelic dropout is capable of leading to the conviction of innocent defendants.
    If our conclusions are accurate, the widely held idea that allelic dropout cannot cause
    false results in a criminal case as long as the same primers/kit are used on both the
    defendant‟s and the perpetrator‟s DNA samples is a very serious falsehood based on the
    improper assumption that the defendant is guilty.
    106.
    d.     “Recovery” of Null Alleles
    The scientific community has devised methods to remedy allelic dropout by
    “recovering” a null allele that has dropped out due to a mutation in a person‟s primer
    binding site. (Recovery also includes routine preemptive practices that prevent a null
    allele from dropping out.) As Myers testified, “there are ways that people have tried to
    deal with [sequence variations that affect primer binding].”
    The recovery of a null allele is based on restoring amplification despite a sequence
    variation in the primer binding site, usually by one of three methods. The first method
    uses a reduced annealing temperature during PCR. The reduced temperature lowers the
    stringency of the hydrogen bonds, thereby promoting binding between the primer and the
    mutant primer binding site, even though they do not match perfectly due to the mutation.
    With this change, the primer binds to the mutated primer binding site, despite the
    mismatch, and amplification will proceed.46 The second method uses degenerate
    primers—a mixture of primers, one of which is specifically designed to match and bind
    to the mutant sequence.47 The new primer binds to the mutated primer binding site,
    because they match, and amplification will proceed.48 The third method uses an entirely
    46     See, e.g., Butler 2005, supra, at pages 135 through 138; Butler 2001, supra, at
    page 92; Hendrickson et al., Accurate STR Allele Designations at the FGA and vWA Loci
    Despite Primer Site Polymorphisms (Mar. 2004) vol. 49, No. 2, J. Forensic Sciences, at
    pages 1 through 5 (reducing annealing temperature improved amplification of alleles with
    primer binding site mutations).
    47     The mutant sequence must be known for a new matching primer to be produced.
    48      See, e.g., Butler 2011, supra, at page 127 (“In some cases, STR kit manufacturers
    have added an additional PCR primer to the assay that can hybridize properly to the
    alternative allele when it exists in a sample. This has been the preferred solution for
    [ABI] …. According to their publications, [ABI] has added an additional primer to
    correct for single point mutations”); Butler 2009, supra, at pages 222 through 223; Butler
    2005, supra, at pages 135 through 138; Butler 2001, supra, at page 92; Leibelt et al.,
    Identification of a D8S1179 primer binding site mutation and the validation of a primer
    designed to recover null alleles, supra, at page 220 (addition of a degenerate primer fully
    107.
    different primer that is designed to bind to a different site on the DNA, often just inside
    or outside of the mutated primer binding site. The different primer binds to the
    nonmutated primer binding site, because they match, and amplification will proceed.49
    In all three methods, the effect of the mutation in the primer binding site is eliminated—
    amplification of the allele occurs as if the mutation did not exist and the null allele is
    recovered.
    Defendant argues that in this case efforts should have been made to recover a
    possible null allele in the perpetrator‟s DNA at the vWA locus to determine whether the
    perpetrator was actually heterozygous at that locus, rather than homozygous like
    defendant. If this had been the result, defendant would have been exonerated.
    To represent this type of recovery, we again begin with the scenario in which the
    defendant is falsely incriminated because one of the perpetrator‟s alleles (the mutant 19*)
    dropped out:
    recovered the null allele in a sample with sequence variation); Leibelt, supra, at page 226
    (ABI‟s Identifiler kit includes degenerate primers for the D8S1179 locus).
    49    See, e.g., Butler 2011, supra, at page 127 (“Promega has moved their primers to
    overcome allele dropout problems”); Butler 2009, supra, at pages 222 through 223.
    The use of kits made by different manufacturers and containing different
    (proprietary) primer sets led to the discovery of null alleles. Now, concordance studies
    are conducted with different kits to discover more null alleles. If two kits containing
    different primers produce different (discordant) results from the same person‟s DNA (one
    kit producing a heterozygous genotype and the other producing a homozygous genotype),
    allelic dropout is suspected as the cause of the homozygous genotype. STRBase lists, for
    example, eight null allele incidents discovered at the vWA locus alone, four of which
    occurred using the Profiler Plus kit but not with another kit: loss of allele 19; loss of
    alleles 15 and 17; loss of allele 16; and loss of alleles 17, 18, and 19
    (http://www.cstl.nist.gov/strbase under Null Alleles, as of May 17, 2013); see Butler
    2011, supra, at pages 126 through 127.
    108.
    allelic dropout
    perp.       14,19*                          false     14,14
    false match
    no allelic dropout
    def.        14,14                           true     14,14
    If the perpetrator‟s mutant 19* allele is recovered, it will amplify and appear as a
    peak. The perpetrator‟s heterozygosity will be exposed (although the mutant 19* will
    appear to be a normal 19). The defendant, who is homozygous, no longer falsely matches
    the perpetrator, and the defendant is correctly exonerated:
    recovery of null allele
    perp.       14,19*                       false        14,19
    true mismatch
    no allelic dropout
    def.        14,14                           true     14,14
    Thus, in this scenario—where one party is mutant heterozygous and the other is
    normal homozygous—the dropout causes a false match and the recovery reveals an
    exonerating mismatch. This is the exonerating null allele recovery to which defendant
    refers.
    But we assume that null allele recovery can also lead to the opposite outcome—an
    incriminating false match—because the recovery itself masks a difference in sequence
    that might exonerate a defendant. The very point of null allele recovery is forcing the
    amplification of an allele despite a sequence variation. If recovery is performed
    preemptively on two samples that are both heterozygous—but one is normal and one is
    mutant—there is a risk of concealing a sequence difference that could have exonerated a
    defendant. We believe the following example demonstrates this possibility.
    If, as before, the perpetrator‟s mutant 19* allele is recovered, it will amplify and
    appear as a peak, and the perpetrator will be considered heterozygous 14,19. But because
    now the defendant is heterozygous 14,19, he will be considered a match even though the
    109.
    perpetrator has the mutation and the defendant does not. The preemptive null allele
    recovery has concealed the fact that the perpetrator‟s 19* allele has a different sequence
    than the defendant‟s 19 allele. If this difference in sequence means the two DNA
    samples come from different people, then this “match” falsely incriminates an innocent
    defendant:
    recovery of null allele
    perp.      14,19*                      false      14,19
    false match
    no allelic dropout
    def.      14,19                          true    14,19
    If instead the mutant 19* allele is not recovered, it fails to amplify and the
    perpetrator appears homozygous. The allelic dropout itself, which occurred because of a
    sequence variation, exonerates the defendant:
    allelic dropout
    perp.      14,19*                        false    14,14
    true mismatch
    no allelic dropout
    def.      14,19                          true    14,19
    Apparently, recovery of a null allele can work in a defendant‟s favor if it happens
    to reveal a heterozygous genotype that exonerates him, or it can work against him if it
    happens to conceal a sequence variation that could have exonerated him. And it may do
    neither. In the following scenario, both allelic dropout and null allele recovery lead to the
    same false match, and the sequence variation simply goes undetected. If both parties are
    homozygous, but the perpetrator has a mutant 19* allele and the defendant has a normal
    19 allele, allelic dropout occurs in one sample and the homozygous genotypes match
    even though one person has a mutation and the other does not:
    110.
    allelic dropout
    perp.    19,19*                           false      19,19
    false match
    no allelic dropout
    def.     19,19                           true       19,19
    If the null allele is recovered, the perpetrator is still homozygous, the mutation is
    still masked, and the genotypes still falsely match:
    recovery of null allele
    perp.    19,19*                       false          19,19
    false match
    no allelic dropout
    def.     19,19                           true       19,19
    These various scenarios demonstrate the limitations of the STR system that result
    from its inherent inability to determine allele sequence. And they raise the issue of
    whether null allele recovery should be conducted in criminal cases and, if so, under what
    circumstances. The prospect that null allele recovery can reveal a heterozygosity that
    exonerates a defendant suggests that recovery should be attempted when an analyst
    observes a homozygous genotype that raises suspicions that a second allele has dropped
    out. But the risk that null allele recovery can mask a sequence variation that could have
    exonerated a defendant suggests that recovery should not be a routine, preemptive
    practice in criminal cases (i.e., with the routine use of reduced annealing temperatures
    and/or degenerate primers). On the other hand, preemptive null allele recovery could be
    viewed simply as a means of restoring the ability of the STR system to measure alleles by
    length without regard for sequence. Alleles with variations in the primer binding site
    would join ranks with alleles with variations inside the STR allele itself. They all would
    be measured by length and all of their sequence variations would go undetected.
    Presumably, the same rationale for tolerating the possibility of an allele matching in
    length but not in sequence would apply to both types of variations: a sequence variation
    111.
    is extremely unlikely to exist in a person whose alleles match in length at a certain
    number of loci.
    We see the obvious value of null allele recovery in parentage and other familial
    testing (e.g., to identify parents, missing children, ancestors, and the remains of victims),
    which relies on the elucidation of familial relationships despite mutations that might have
    occurred between generations. And we see the value of null allele recovery when
    comparing DNA profiles that have been created with different primer sets (e.g., kits from
    different manufacturers). But we think the value of null allele recovery within a criminal
    case—where the purpose is to determine whether two DNA samples come from the same
    person—is a more complicated issue. If the ultimate test of identity between two DNA
    samples is the identity of their sequences, then methods that suppress or mask sequence
    differences may not be appropriate in the criminal context.
    It is our hope in discussing these issues that the scientific community will
    reexamine the possible effects and management of allelic dropout in criminal cases and
    determine how best to safeguard the innocent while incriminating the guilty.
    e.     The Present Case
    In this case, Myers‟s opinion was that allelic dropout would not cause a false
    result because “the person who would have that sample would still type as this same
    result using this kit. So as long as everyone is typed with the same kit there wouldn‟t be
    any false result because the result will be the same.” Myers did not expressly refer to the
    samples coming from the same person, as Butler and the other authors do in the excerpts
    above. But if Myers‟s opinion was also based on the assumption that defendant and the
    perpetrator were the same person—that defendant was guilty—then it was based on an
    incorrect legal theory. And, if so, the opinion did not constitute substantial evidence that
    allelic dropout did not cause, or could not have caused, a false match in this case.
    (Corrales v. Corrales (2011) 
    198 Cal.App.4th 221
    , 226 [“An expert‟s opinion that
    assumes an incorrect legal theory cannot constitute substantial evidence”]; Exxon Corp.
    112.
    v. Superior Court (1997) 
    51 Cal.App.4th 1672
    , 1683 [“court is not bound by an expert
    opinion that is speculative or conjectural or that is based on an incorrect legal theory”];
    Pacific Gas & Electric Co. v. Zuckerman (1987) 
    189 Cal.App.3d 1113
    , 1135 [“The value
    of opinion evidence rests not in the conclusion reached but in the factors considered and
    the reasoning employed”; “Where an expert bases his conclusion upon assumptions
    which are not supported by the record, upon matters which are not reasonably relied upon
    by other experts, or upon factors which are speculative, remote or conjectural, then his
    conclusion has no evidentiary value”]; see also Sargon Enterprises, Inc. v. University of
    Southern California (2012) 
    55 Cal.4th 747
    , 771 [“„A court may conclude that there is
    simply too great an analytical gap between the data and the opinion proffered‟”].)
    Assuming, without deciding, that Myers‟s opinion was flawed and the trial court
    abused its discretion in not excluding it, we consider whether it is reasonably probable
    that the verdict would have been more favorable to defendant in the absence of the error.
    (People v. Prieto (2003) 
    30 Cal.4th 226
    , 247 [erroneous admission of expert testimony
    reviewed under Watson standard]; Venegas, 
    supra,
     18 Cal.4th at p. 93; Watson, supra, 46
    Cal.2d. at p. 836.) Had the trial court excluded Myers‟s opinion, the remaining evidence
    on this topic would have constituted the following: The sperm fraction
    electropherograms showed single peaks at three loci—vWA, TPOX, and CSF1PO.
    Myers explained that all of these single peaks were of great enough height that he saw no
    reason to suspect, based on peak height, that a second allele had dropped out.50 He also
    noted that although some degradation of the DNA had occurred in this case, it was not
    sufficient to concern him. Furthermore, allelic dropout is a rare phenomenon, occurring
    at a frequency of about 0.1 percent.51 Even without Myers‟s potentially flawed opinion,
    50     The single peaks at the vWA, TPOX, and CSF1PO loci were over 8,000 RFU,
    over 1,200 RFU, and over 500 RFU, respectively.
    51    We note that STRBase lists the frequency of reported primer binding site
    mutations causing null alleles at the STR loci. Some mutations were found to appear as
    113.
    we believe this remaining evidence was sufficient to establish that Myers considered the
    possibility of allelic dropout, looked for signs suggesting it might have occurred, and
    concluded, based on his experience and observations, that it had not occurred here and
    that the single peaks represented true homozygous genotypes.
    If, however, Myers did not follow correct scientific procedure in his analysis of
    the possibility of allelic dropout and thus the trial court should have excluded the
    evidence of the single peaks at the three loci because allelic dropout could have occurred
    at those loci, we would still conclude the court‟s failure to exclude that evidence was
    harmless. If the three apparently homozygous loci had not been considered because their
    single peaks were inconclusive based on the possibility of allelic dropout, the remaining
    loci still would have constituted a 10-loci match that still would have produced
    astronomically rare statistics and still would have been extremely incriminating.
    Defendant could argue he might not even have matched at those three loci if allelic
    dropout had occurred at any one of them and therefore they cannot just be ignored. But it
    is always true that a match might not occur at additional loci if they are tested, even if
    that possibility is extremely unlikely in light of many loci already matching. The
    argument, however, is speculative and does not change our conclusion.
    In summary, if Myers‟s opinion was improperly based on the assumption that
    defendant was guilty, any error in admitting the opinion was nevertheless harmless.
    Other evidence showed that allelic dropout had probably not occurred at the three
    apparently homozygous loci. Furthermore, even if evidence of the three apparently
    homozygous loci should have been excluded, a 10-loci match would have been extremely
    frequently as three in 110 and some as infrequently as one in 18,314.
    (http://www.cstl.nist.gov/strbase under Null Alleles, as of May 17, 2013.) The website
    also lists mutation rates of each of the core STR loci as ranging from 0.01 percent to
    0.28 percent. (http://www.cstl.nist.gov/strbase under Mutation Rates for Common Loci,
    as of May 17, 2013.)
    114.
    incriminating, even though less so than a 13-loci match. We conclude there is no
    reasonable probability of a more favorable verdict without Myers‟s opinion and even
    without the three apparently homozygous loci. Any error was harmless. (People v.
    Prieto, 
    supra,
     30 Cal.4th at p. 247 Venegas, 
    supra,
     18 Cal.4th at p. 93; Watson, supra, 46
    Cal.2d. at p. 836.)
    III.   AGREEMENT OF FACTS COMPRISING MURDER*
    The trial court instructed the jury on two theories of first degree murder:
    premeditation and felony murder. Defendant contends the trial court violated his Sixth
    Amendment right to a jury trial when it permitted the jury to convict him of murder
    without agreeing on the facts that comprise the offense.
    In Schad v. Arizona (1991) 
    501 U.S. 624
    , 630-645 (Schad) and Walton v. Arizona
    (1990) 
    497 U.S. 639
    , 648 (Walton), overruled on another ground by Ring v. Arizona
    (2002) 
    536 U.S. 584
    , 609 (Ring), the United States Supreme Court held that federal
    courts would defer to states‟ definitions of the elements of offenses, and juror unanimity
    was not required as to the factual theory for a conviction. The California Supreme Court
    has explicitly held that “jurors need not unanimously agree on a theory of first degree
    murder .…” (People v. Nakahara (2003) 
    30 Cal.4th 705
    , 712 (Nakahara).) Defendant
    argues that the United States Supreme Court‟s decisions in Apprendi v. New Jersey
    (2000) 
    530 U.S. 466
     (Apprendi) and Ring have undercut the basis for Nakahara.
    In Ring, the court overruled Walton “to the extent that it allows a sentencing judge,
    sitting without a jury, to find an aggravating circumstance necessary for imposition of the
    death penalty.” (Ring, 
    supra,
     536 U.S. at p. 609.) However, neither Ring nor Apprendi
    mentioned Schad. Furthermore, in Nakahara, the California Supreme Court rejected the
    argument that Apprendi called into question former rulings that unanimity instructions
    are not required when a jury is instructed on different theories of first degree murder.
    *      See footnote, ante, page 1.
    115.
    The court explained that in Apprendi, “the United States Supreme court found a
    constitutional requirement that any fact that increases the maximum penalty for a crime,
    other than a prior conviction, must be formally charged, submitted to the fact finder,
    treated as a criminal element, and proved beyond a reasonable doubt. [Citation.] We see
    nothing in Apprendi that would require a unanimous jury verdict as to the particular
    theory justifying a finding of first degree murder. (See also Ring[, supra,] 536 U.S. [at
    p. 610] [requiring jury finding beyond reasonable doubt as to facts essential to
    punishment].)” (Nakahara, 
    supra,
     30 Cal.4th at pp. 712-713; see also People v. Quiroz
    (2013) 
    215 Cal.App.4th 65
    , 73-76.) In People v. Hawthorne (2009) 
    46 Cal.4th 67
     at
    page 89, overruled on another point in People v. McKinnon (2011) 
    52 Cal.4th 610
     at
    page 637, the court reaffirmed that a unanimity instruction is not required when two
    theories of first degree murder are presented.
    We are bound by Nakahara and Hawthorne (Auto Equity Sales, Inc. v. Superior
    Court (1962) 
    57 Cal.2d 450
    , 455), and therefore we reject defendant‟s contention that the
    jury should have been instructed on unanimity as to the theory of murder.
    DISPOSITION
    The judgment is reversed.
    _____________________
    Kane, Acting P.J.
    WE CONCUR:
    _____________________
    Poochigian, J.
    _____________________
    Franson, J.
    116.