People v. Brown ( 2016 )


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  • Filed 2/25/16
    CERTIFIED FOR PUBLICATION
    IN THE COURT OF APPEAL OF THE STATE OF CALIFORNIA
    FIRST APPELLATE DISTRICT
    DIVISION FOUR
    THE PEOPLE,
    Plaintiff and Respondent,
    A141172
    v.
    WILBERT BROWN,                                      (Contra Costa County
    Super. Ct. No. 121946-8)
    Defendant and Appellant.
    I.
    INTRODUCTION
    In November 2011, Wilbert Brown was riding his bicycle on a sidewalk one
    evening in Richmond when Officer Michael Ricchiuto ordered him to stop for wearing
    earphones while riding, and for not having a light. Brown, who was 67 years old at the
    time, attempted to flee, but Ricchiuto and a second officer, Officer James Moody, chased
    him down and arrested him. After a physical altercation during the arrest, the officers
    restrained Brown and found drugs in a baggie he had discarded during the chase.
    Charges arising out of this incident resulted in felony convictions for possession and
    transportation of cocaine and for using force or violence to resist an executive officer in
    the performance of his duty in violation of Penal Code section 69 (section 69). Brown
    appeals, seeking reversal of his conviction for violating section 69 on two grounds:
    (1) the failure to instruct the jury sua sponte regarding simple assault as a lesser
    necessarily included offense, and (2) the erroneous admission of expert testimony
    regarding police standards for use of force. We agree with both contentions and shall
    conditionally reverse, finding that these errors, considered individually and cumulatively,
    1
    require either a modification or reversal of Brown’s conviction for resisting an officer by
    force or violence.1
    II.
    STATEMENT OF FACTS AND PROCEDURE
    A.     Brown’s Arrest on November 14, 2011: The Officers’ Version vs.
    Brown’s Version
    The initial series of events leading to Brown’s arrest was undisputed. Near dusk
    on November 14, 2011, Officer Ricchiuto was on patrol in his cruiser in the Iron Triangle
    area of Richmond, a neighborhood known for drug trafficking and gang activity, often
    involving young African American men. He spotted Wilbert Brown, a 67-year-old
    African American man, riding a bicycle on the sidewalk in violation of the Richmond
    Municipal Code, while wearing headphones and without a light in violation of the
    California Vehicle Code. Officer Ricchiuto yelled at Brown to stop, but Brown sped up
    and tried to flee, with Officer Ricchiuto in pursuit. Another officer, Officer Moody, who
    was backing up Ricchiuto in a second cruiser, joined in the chase and at one point
    wedged his car in front of Brown’s path in an effort to cause a collision. Brown managed
    to steer around Moody’s car, grazing it and breaking a side mirror as he passed. Both
    officers eventually left their vehicles and pursued Brown on foot. The officers cornered
    Brown in an abandoned parking lot, where they arrested him after a brief altercation. In
    the course of that altercation, Brown sustained a fractured rib and knots on his head,
    while Officer Ricchiuto sustained a “boxer’s fracture” to the knuckle of his right hand.
    At the time of their encounter with Brown, both officers were several decades younger
    1
    Brown also seeks review of the denial of a pretrial motion for discovery of the
    personnel records of the officers involved in the incident pursuant to Pitchess v. Superior
    Court (1974) 
    11 Cal. 3d 531
    (Pitchess). Having reviewed the withheld personnel records,
    we affirm the trial court’s denial of Brown’s Pitchess motion. On August 1, 2014, this
    court filed an order indicating that we had reviewed the sealed record of the Pitchess
    proceeding and found “that there are no discoverable documents under seal that should be
    produced to counsel.” In his opening brief, appellant requests a second review be
    conducted with the “benefit” of his factual summary and legal analysis. The disposition
    we reach reaffirms our August 1, 2014 order.
    2
    than Brown (Ricchiuto was in his “late 20s” and Moody was 38), and in excellent
    physical condition. They were also physically much bigger than Brown (Brown was 5’
    8”, 140 pounds, while the officers were 6’ 0’’, 175 and 200 pounds respectively).
    What happened in the parking lot when the officers caught Brown was a matter of
    some dispute.
    According to the officers, at that point they had no idea how old Brown was. To
    them, he was a man they had never seen before, who was wearing baggy clothes, and
    who, by this stage of the chase, was suspected of felony drug trafficking. Officer Moody
    caught up to Brown first, yelled at him repeatedly to stop, and then tackled him, throwing
    him off of his bicycle, and taking him to the ground. Brown “aggressively” “flipp[ed]
    back over” into a “sitting position”, and became combative, “swinging his hands” with a
    “clenched fist.” To get control of Brown and protect himself, Officer Moody used his fist
    to hit Brown in the torso area with a “compliance strike,” but the punch had no effect and
    Brown continued to swing at him; at that point, Officer Ricchiuto came to Officer
    Moody’s assistance, and, seeing Brown reach for something in his waistband, delivered
    three “compliance strikes,” one with his knee to Brown’s torso, and two with his fists to
    the side of Brown’s head. These blows caused Brown to stop swinging2 and shield his
    head with his hands, a defensive move that finally brought him under control, since it
    allowed the officers to secure his hands and place him in handcuffs. Brown’s account of
    the officers’ actions was quite different. He testified that he fell off his bicycle in the
    parking lot after hitting a curb. He claimed that, without any kind of warning, and while
    he was face-down on the ground, not resisting and no longer fleeing, one of the officers
    dived on his back with enormous force, “like Superman,” pinning him down. That
    officer, angry and unprovoked, then proceeded to slug him in the head three times. In
    2
    Both officers were wearing bullet-proof vests. Officer Moody testified that
    Brown never succeeded in hitting him. Officer Ricchiuto testified that Brown hit him
    twice. Neither suffered injuries from what Officer Moody described as Brown’s
    “flail[ing]” at them.
    3
    Brown’s telling, all the second officer did was handcuff him after he had been pummeled
    by the first officer. Brown denied swinging at either officer. He testified, “I wouldn’t
    even try to—I couldn’t win anyway, but no, I didn’t.”
    B.     Expert Testimony
    The prosecution presented the testimony of three experts to support its case, the
    first two to support the drug charges and the third to support the charge of resisting an
    executive officer with force or violence. Criminalist Richard Bowden testified as an
    expert in the area of analyzing controlled substances. Bowden was asked to examine a
    packet of 10 knot-tied plastic bags containing an off-white chunky substance that had
    been contained in the baggie Brown discarded. Bowden tested one of the bags and
    concluded it contained .219 grams of cocaine base. Bowden offered the opinion that the
    other packets, which contained substantially similar amounts of what appeared to be the
    same substance, were also cocaine. The total estimated net weight of the substance in all
    10 bags was 1.799 grams.
    Detective Miguel Castillo of the Richmond Police Department (RPD) testified as
    an expert on the subject of possession of cocaine base for sale. Castillo opined that when
    a person is carrying narcotics for sale rather than for personal use, he holds the drugs in
    individual use packages in order to make speedy transactions, maximize profits, and
    avoid carrying a scale. A “street-level dealer” also avoids having to use “pay/owe”
    sheets by packaging narcotics in a single dose amount, which is approximately .2 grams.
    When asked about a hypothetical suspect who was in possession of the amount and type
    of substances that Ricchiuto found when chasing Brown, Castillo opined that the drugs
    belonged to a street-level dealer who sells useable amounts of cocaine base.
    Under cross examination, Castillo testified that a single dose of rock cocaine has
    an effect on the user for approximately 30 to 40 minutes and that the typical user may
    partake of this drug several times a day. In Castillo’s experience, however, most users
    buy only one dose at a time, get high from it, and then go back to their suppliers for more,
    instead of simply buying several doses at one time. Castillo conceded that in the 15 cases
    4
    in which he had testified as an expert regarding possession of cocaine for sale, the
    amount of drugs in question was never as small as 1.7 grams.
    Another RPD officer, Sergeant Albert Walle, provided expert testimony on the
    subject of police officer “defensive tactics.” The prosecutor began her examination of
    Walle by asking about the legal authority of the police to use reasonable force. Walle
    testified that Penal Code section 835 authorizes the police to “use reasonable force when
    necessary when a public offense has been committed in order to effect an arrest, prevent
    an escape or overcome resistance.” Walle also explained that the concept of “reasonable
    force” is defined in a 1989 Supreme Court case called Graham v. Connor.3 When asked
    for the “general gist” of what reasonable force means, Walle stated: “Whenever you’re
    using force, try to look at the totality of the circumstances through the perspective of the
    officer at the time who was using force, keeping in mind that the situation is fluid,
    evolving, and there’s also various factors that come in that as well, too.”
    Walle testified that when officers have to use reasonable force their primary
    objective is to subdue suspects by overcoming their resistance and detaining them safely.
    The main factor affecting the officer’s decision about what force to use will be the
    suspect’s “resistance level” because the officer is going to be responding to what the
    suspect is doing. To teach officers how to respond appropriately, RPD employs a “use of
    force continuum,” which consists of a ladder of escalation of resistance on one side
    matched against a ladder of escalation of force by the officer on the other side. Officers
    are taught not to look at an altercation as a “fair fight,” but to employ a higher level of
    force than he or she faces: “You don’t want to bring a baton to a knife fight, so you also
    want to be at least one level higher than what you’re . . . encountering.”
    Walle outlined other important considerations for an officer who faces resistance
    from a suspect, which include the need to react and take control as quickly as possible to
    avoid fatigue; the importance of gaining control of the suspect’s hands because of their
    potential to injure the officer; and the need to be attuned to movements toward the waist
    3
    See Graham v. Connor (1989) 
    490 U.S. 386
    (Graham).
    5
    area because it is common to keep a weapon there. Walle testified that an officer does
    not have “control” of a suspect until he or she stops resisting. The “tools” officers carry,
    Walle testified, include a gun, handcuffs, pepper spray, a taser, baton, and a flashlight. In
    addition, the officers are taught to use their “personal weapons,” which include hands,
    forearms, elbows, knees and feet. Different tools are appropriate for different levels of
    force. Using body parts or a baton is considered “lower level force,” while a taser is an
    “intermediate” level, and a firearm is the highest level of force.
    The prosecutor asked Walle to address a hypothetical situation in which a suspect
    was using a closed fist to swing at and attempt to punch an officer. Walle characterized
    that hypothetical suspect as engaging in “assaultive” behavior. In that situation, officers
    are trained to use either personal body weapons, a taser, baton or pepper spray. Officers
    are also trained to provide assistance to an officer dealing with assaultive behavior
    because it is usually easier to gain control when another officer assists, and gaining
    control quickly is important for the safety of the officers as well as the suspect. Walle
    testified that “[m]ost use-of-force incidences happen within a matter of seconds, and
    they’re constantly evolving and they’re very dynamic, and an officer has to think on his
    feet very fast, and oftentimes doesn’t have time—has to be very instinctive and a lot of it
    is responsive to training.”
    C.     Jury Verdict and Sentence
    The jury was instructed on two felony drug charges: possession for sale of cocaine
    base (Health & Saf. Code, § 13351.5); and transporting cocaine base (Health & Saf.
    Code, § 11352). It also received instruction regarding possession of cocaine base (Health
    & Saf. Code, § 11350), as a lesser offense of the possession for sale charge. The jury
    also was instructed on the charge that Brown violated section 69, the offense which is the
    subject of this appeal. Section 69, subdivision (a) states: “Every person who attempts,
    by means of any threat or violence, to deter or prevent an executive officer from
    performing any duty imposed upon the officer by law, or who knowingly resists, by the
    use of force or violence, the officer, in the performance of his or her duty, is punishable
    by a fine not exceeding ten thousand dollars ($10,000), or by imprisonment pursuant to
    6
    subdivision (h) of Section 1170, or in a county jail not exceeding one year, or by both
    such fine and imprisonment.”
    Section 69 can be violated in two separate ways. “ ‘The first is attempting by
    threats or violence to deter or prevent an officer from performing a duty imposed by law;
    the second is resisting by force or violence an officer in the performance of his or her
    duty.’ ” (People v. Smith (2013) 
    57 Cal. 4th 232
    , 240 (Smith).) In this case, the jury was
    instructed about the second type of section 69 violation which requires the prosecution to
    prove the defendant knowingly resisted the officer “ ‘by the use of force or violence,’ ”
    and “that the officer was acting lawfully at the time of the offense.” (Id. at p. 241.) At
    the request of both the prosecution and the defense, the jury was provided with the option
    of convicting Brown of misdemeanor resisting an officer during the lawful performance
    of his duties in violation of Penal Code section 148, subdivision (a) (section 148(a)), as a
    lesser included offense of the section 69 felony charge. The theory of Brown’s defense to
    the section 69 charge was that the officers did not act lawfully when they arrested him
    because they used unreasonable and excessive force. The instructional guidance the jury
    received on this issue was CALCRIM No. 2670, which provides that “A peace officer
    may use reasonable force to arrest or detain someone, to prevent escape, to overcome
    resistance, or in self-defense.”4
    4
    Neither party requested a special jury instruction giving the jury further guidance
    as to what constitutes “reasonable force” under Graham. The CALCRIM No. 2670
    instruction the jury received, however, did elaborate in another respect, providing
    guidance as to the lawfulness of an arrestee’s conduct when confronted with
    unreasonable or excessive force by an officer. “If a peace officer uses unreasonable or
    excessive force while . . . arresting . . . a person, that person may lawfully use reasonable
    force to defend himself or herself,” which is in turn defined as “that degree of force he or
    she actually believes is reasonably necessary to protect himself or herself from the
    officer’s use of unreasonable or excessive force” and “no more force than a reasonable
    person in the same situation would believe is necessary for his or her protection.”
    (CALCRIM No. 2670.) But the criteria by which to evaluate objective reasonableness—
    whether from a reasonable officer’s perspective or from the arrestee’s—were, in this
    case, left to the jury.
    7
    On October 4, 2013, the jury returned its verdicts, finding Brown not guilty of
    possession of cocaine base for sale, but guilty of the lesser included offense of possession
    of cocaine base; guilty of transportation of cocaine base; and guilty of using force or
    violence to resist an officer in the lawful performance of his duties in violation of section
    69. Brown was sentenced in January 2014. The trial court granted a defense motion to
    dismiss the transportation conviction based on intervening legislation limiting that
    offense to transportation for sale. (See Health & Saf. Code, § 11352, subd. (c), added by
    Stats. 2013, ch. 504, § 1 (AB 721).) The court denied a defense motion to reduce the
    section 69 conviction to a misdemeanor, however, because Brown’s decision to flee
    caused both property damage and personal injury (Brown’s bike “wiped out” the mirror
    on the officer’s patrol car, and the officer injured his hand because of the contact with
    Brown). After considering the relevant sentencing factors, the court placed Brown on
    three years felony probation with a suspended 120-day jail term as a condition of
    probation.
    III.
    DISCUSSION
    A.     The Instructional Error
    1.     Issue Presented
    Framing the case as a choice between two starkly different scenarios, one
    recounted by the officers, or the other recounted by Brown, the Attorney General
    contends the jury chose the first, resolving a simple credibility contest in favor of the
    officers. That may be so, Brown responds, but by failing to instruct the jury on the lesser
    included offense of simple assault, the court never gave the jury the option of finding that
    both versions of the facts were partly true. He points out, for example, that even if the
    jury believed he swung at the officers, it reasonably might have found that his punches
    were feckless, yet drew a severe and wholly unnecessary beating in response. Without
    commenting on which version of events here was the more persuasive, we conclude that
    Brown’s assignment of instructional error has merit, that the jury should have been given
    the option of finding him guilty of simple assault, and that he was prejudiced by the error.
    8
    As noted above, a violation of section 69 can occur in two circumstances. Under
    that section, a defendant commits a violation by attempting to deter an officer’s lawful
    duty by violence or threat of violence. Alternatively, section 69 is violated where a
    defendant knowingly resists an officer’s execution of lawful duty by actually using force
    or violence. 
    (Smith, supra
    , 57 Cal.4th at p. 240.) Because the second ground for section
    69 liability was the sole theory the prosecutor pursued at trial, the jurors were instructed
    that they could convict for violation of section 69 only if they found actual use of force or
    violence. At the request of both Brown and the prosecutor, the instructions gave the jury
    the option of finding Brown guilty of misdemeanor resisting an officer during the lawful
    performance of his duties as a lesser included offense of the section 69 charge. Under
    this lesser charge, the jury could have convicted Brown had it found that Brown resisted
    the officers’ lawful performance of their duties, even if he did not use force or violence to
    effectuate that resistance. (See § 148(a).) Brown contends on appeal that the jury should
    have been given an additional option—convicting him of misdemeanor simple assault as
    a lesser included offense to a section 69 violation.
    An assault is “an unlawful attempt, coupled with a present ability, to commit a
    violent injury on the person of another.” (Pen. Code, § 240 (section 240).) An “assault
    does not require a specific intent to cause injury or a subjective awareness of the risk that
    an injury might occur. Rather, assault only requires an intentional act and actual
    knowledge of those facts sufficient to establish that the act by its nature will probably and
    directly result in the application of physical force against another.” (People v. Williams
    (2001) 
    26 Cal. 4th 779
    , 790.) Brown asserts that a conviction for assault could have been
    supported by trial evidence that he used force to resist the officers under circumstances
    where the jury found the officers responded with excessive force, a factual scenario
    falling somewhere between the officers’ version of events in the parking lot and that of
    Brown.
    Brown concedes that he did not request an assault instruction, but he contends that
    the trial court had a sua sponte duty to instruct on assault as a lesser included offense of
    the section 69 charge. “ ‘California law has long provided that even absent a request, and
    9
    over any party’s objection, a trial court must instruct a criminal jury on any lesser offense
    “necessarily included” in the charged offense, if there is substantial evidence that only the
    lesser crime was committed. This venerable instructional rule ensures that the jury may
    consider all supportable crimes necessarily included within the charge itself, thus
    encouraging the most accurate verdict permitted by the pleadings and the evidence.’
    [Citation.] ‘[T]he rule prevents either party, whether by design or inadvertence, from
    forcing an all-or-nothing choice between conviction of the stated offense on the one hand,
    or complete acquittal on the other. Hence, the rule encourages a verdict, within the
    charge chosen by the prosecution, that is neither “harsher [n]or more lenient than the
    evidence merits.” [Citations.]’ [Citation.] Thus, ‘a trial court errs if it fails to instruct,
    sua sponte, on all theories of a lesser included offense which find substantial support in
    the evidence. On the other hand, the court is not obliged to instruct on theories that have
    no such evidentiary support.’ ” 
    (Smith, supra
    , 57 Cal.4th at pp. 239–240.)
    “ ‘ “We apply the independent or de novo standard of review to the failure by the
    trial court to instruct on an assertedly lesser included offense. [Citation.]” ’ [Citation.]”
    (People v. Campbell (2015) 
    233 Cal. App. 4th 148
    , 158.)
    2.      Analysis
    “Under California law, a lesser offense is necessarily included in a greater offense
    if either the statutory elements of the greater offense, or the facts actually alleged in the
    accusatory pleading, include all the elements of the lesser offense, such that the greater
    cannot be committed without also committing the lesser.” (People v. Birks (1998) 
    19 Cal. 4th 108
    , 117–118 (Birks).)
    The question whether assault is a lesser necessarily included offense of section 69
    is somewhat complicated by the fact that section 69 can be violated in two separate ways,
    as we explained earlier. A person can commit this felony either by (1) attempting by
    threats or violence to deter or prevent an officer from performing a duty imposed by law,
    or (2) by knowingly resisting through the actual use of force or violence against an
    officer in the performance of his or her duty. 
    (Smith, supra
    , 57 Cal.4th at p. 240.) A
    person can violate section 69 in the first way without necessarily attempting to apply
    10
    physical force. (See In re Manuel G. (1997) 
    16 Cal. 4th 805
    , 817 [defendant can commit
    first type of offense prohibited by section 69 by threatening an officer in an attempt to
    deter officer from future performance of a duty].) Under this formulation, a person can
    violate section 69 without also violating section 240, which defines an assault as “an
    unlawful attempt, coupled with a present ability, to commit a violent injury on the person
    of another.” Therefore, as Brown concedes, section 240 is not a lesser included offense
    of section 69 under the statutory elements test.
    Under the accusatory pleading test, however, we consider whether the facts
    alleged in the accusatory pleading include all the statutory elements of an assault. 
    (Birks, supra
    , 19 Cal.4th at pp. 117–118.) Here, although the prosecutor’s trial theory was that
    Brown committed the second type of section 69 violation, the first amended information
    was not so limited. It alleged that Brown violated section 69 not just by attempting to
    deter or prevent the officer from performing his duties (which can be accomplished
    without force), but also by knowingly resisting the officers with force and violence.
    Because the accusatory pleading used the conjunctive to charge Brown with both ways of
    violating section 69, and it is not possible to violate the statute in the second way without
    committing an assault, we conclude that assault was necessarily a lesser included offense
    of section 69 under the accusatory pleading test. (See 
    Smith, supra
    , 57 Cal.4th at
    pp. 242–243 [§ 148(a) was necessarily a lesser offense of § 69 when accusatory pleading
    charged the defendant with both ways of violating § 69].)
    The Attorney General concedes “[f]or purposes of this appeal . . . that section 240
    was a necessarily included offense of section 69 as alleged in the amended information.”
    But she nonetheless contends an assault instruction was not required in this case because
    there was no evidence that Brown’s offense was less than the crime charged.
    “[I]nstructions on lesser included offenses ‘are required whenever evidence that the
    defendant is guilty only of the lesser offense is “substantial enough to merit
    consideration” by the jury. [Citations.] “Substantial evidence” in this context is
    “ ‘evidence from which a jury composed of reasonable [persons] could . . . conclude[]’ ”
    that the lesser offense, but not the greater, was committed. [Citations.]’ [Citation.]
    11
    Instructions on lesser included offenses should be given ‘when the evidence raises a
    question as to whether all of the elements of the charged offense were present [citation],
    but not when there is no evidence that the offense was less than that charged.’
    [Citations.]” (People v. 
    Campbell, supra
    , 233 Cal.App.4th at p. 162.)
    Specifically, the Attorney General contends there was no evidence from which the
    jury could have concluded that Brown committed an assault without also violating
    section 69. She reasons that the jury was faced with a choice of either (1) crediting the
    prosecution evidence, which would establish that Brown forcibly resisted the officers and
    that the officers used reasonable force, or (2) crediting Brown’s story, which would have
    established that the officers used excessive force and Brown was “completely
    unaggressive and defenseless.” This reading of the record misconstrues the function of
    the jury in the truth seeking process. “ ‘Our courts are not gambling halls but forums for
    the discovery of truth.’ [Citation.] Truth may lie neither with the defendant’s
    protestations of innocence nor with the prosecution’s assertion that the defendant is guilty
    of the offense charged, but at a point between these two extremes: the evidence may
    show that the defendant is guilty of some intermediate offense included within, but lesser
    than, the crime charged.” (People v. Barton (1995) 
    12 Cal. 4th 186
    , 196.) Thus, the jury
    was not required to choose and fully credit only one of the two versions of the November
    2011 incident that were presented to it. For example, the jury could also have concluded
    that Brown used force or violence to resist arrest but that the officers nonetheless
    responded with unreasonable force. Under that scenario, Brown could have been found
    not guilty of the section 69 violation, but still guilty of the lesser crime of assault.
    Alternatively, the Attorney General argues that the trial evidence established that
    the officers used reasonable force as a matter of law. Reasoning that Sergeant Walle’s
    testimony established that the officers were legally entitled to use a level of force that
    was more than one level above the level of force used by the suspect, respondent
    contends that there is no evidence “in the record that would support a finding that the
    officers’ conduct was anything more than one level above that employed by [Brown] or
    that it continued longer than necessary to gain control of [Brown].” The premise of this
    12
    argument—that Sergeant Walle’s testimony was properly admitted—is incorrect for
    reasons we explain below, but even had the testimony been narrowly enough framed and
    appropriate for admission, the argument fundamentally misconceives the proper role of
    expert testimony in a case of this nature. Such testimony can never be used to define, as
    a matter of law, what constitutes objectively reasonable force or to decide whether it was
    used in a given case.
    As we have posited, the trial evidence would substantially support a jury finding
    that, although Brown attempted to use force to resist arrest, the officers overreacted with
    excessive force and, therefore, were not acting within the scope of their duties. “[A]
    resisting defendant commits a public offense; but if the arrest is ultimately determined
    factually to be unlawful, the defendant can be validly convicted only of simple assault or
    battery.” (People v. Curtis (1969) 
    70 Cal. 2d 347
    , 355–356.) Thus, we conclude that the
    trial court erred by failing to instruct the jury regarding assault as a lesser necessarily
    included offense of the section 69 charge. “ ‘[T]he failure to instruct sua sponte on a
    lesser included offense in a noncapital case is, at most, an error of California law alone,
    and is thus subject only to state standards of reversibility.’ [Citation.] Under the state
    standard, ‘such misdirection of the jury is not subject to reversal unless an examination of
    the entire record establishes a reasonable probability that the error affected the outcome.’
    [Citations.] ‘The Supreme Court has emphasized “that a ‘probability’ in this context does
    not mean more likely than not, but merely a reasonable chance, more than an abstract
    possibility. [Citations.]” [Citation.]’ ” (People v. 
    Campbell, supra
    , 233 Cal.App.4th at
    p. 165.) Under this test, we find a reasonable probability the error affected the outcome
    of this case. The use of excessive force was a primary defense theory at trial and there
    was substantial evidence to support it. But the instructional error precluded the jury
    from finding that the officers used excessive force, while convicting Brown of assault for
    swinging at the officers in a manner that could have injured them, whether he intended to
    cause injury or not. A “jury without an option to convict a defendant of a lesser included
    offense might be tempted to convict the defendant of an offense greater than that
    13
    established by the evidence instead of rendering an acquittal.” (People v. Eid (2014) 
    59 Cal. 4th 650
    , 658.)
    Furthermore, this jury showed a readiness to scrutinize the evidence, draw its own
    independent conclusions of Brown’s level of culpability, and convict on lesser charges
    than the prosecutor requested. The jury convicted Brown of a lesser included offense on
    the drug charge, for example, which is an indication that it had doubts about the
    prosecution’s case which might also have affected its resolution of the section 69 charge.
    (See People v. Mullendore (2014) 
    230 Cal. App. 4th 848
    , 857 [doubts leading jury to
    convict defendant of lesser offense of one charge could have led to a similar result on
    another charge for which it was not given that option].) Brown contends that the jury
    convicted him of simple possession rather than possession for sale because it had doubts
    about the credibility of the officers’ story that Brown threw the bag of cocaine rocks
    under the parked car. Alternatively, that verdict may indicate that the jury drew different
    conclusions from expert evidence about possession of cocaine for sale than the prosecutor
    had intended. In any event, the jury could have had similar doubts about the section 69
    charge. As discussed above, the defense argued that, even though Brown may have used
    force to resist arrest, the officers overreacted and administered a beating that was
    unreasonable and excessive. The instructional error precluded the jury from deciding
    whether to credit the substantial evidence supporting this theory.
    The Attorney General’s only harmless error argument is that the instructional error
    did not affect the outcome because “in convicting [Brown] of violating section 69 the
    jury showed it rejected [Brown’s] claim of excessive force and found that the level of
    force used by the officers was at all times reasonable.” But in assessing prejudice, “it
    does not matter that the jury chose to convict the defendant of the greater offense over
    acquittal or that the defendant was convicted of the greater offense on sufficient
    evidence.” (People v. Racy (2007) 
    148 Cal. App. 4th 1327
    , 1335–1336.) To hold
    otherwise would undermine the very purpose of the sua sponte rule. (People v.
    Breverman (1998) 
    19 Cal. 4th 142
    , 178, fn. 25.) It does seem abundantly clear, however,
    as the Attorney General points out, that the jury found that Brown swung his fists at one
    14
    or more of the officers during the course of the arrest. Whether these blows (or attempted
    blows) were effectual or not, we find substantial evidence to support an assault
    conviction. “When a greater offense must be reversed, but a lesser included offense
    could be affirmed, we give the prosecutor the option of retrying the greater offense, or
    accepting a reduction to the lesser offense.” (People v. Kelly (1992) 
    1 Cal. 4th 495
    , 528;
    see People v. Hayes (2006) 
    142 Cal. App. 4th 175
    , 184.) On remand we will provide the
    prosecution with the option of retrying the section 69 charge along with a charge of
    simple assault, subject to the guidance provided below in Part III.B.
    B.     Admission of Expert Testimony on Police Use of Force
    1.     Principles Governing Admission of Expert Testimony Generally
    We review the trial court’s ruling on the admissibility of expert testimony for
    abuse of discretion. (Sargon Enterprises, Inc. v. University of Southern California (2012)
    
    55 Cal. 4th 747
    , 773 (Sargon).) A ruling that constitutes an abuse of discretion has been
    described as one that is “ ‘so irrational or arbitrary that no reasonable person could agree
    with it.’ ” (Ibid.) But the trial court’s discretion is not unlimited. “ ‘The scope of
    discretion always resides in the particular law being applied, i.e., in the “legal principles
    governing the subject of [the] action . . . .” Action that transgresses the confines of the
    applicable principles of law is outside the scope of discretion and we call such action an
    “abuse” of discretion. [Citation.] . . . [¶] The legal principles that govern the subject of
    discretionary action vary greatly with context. [Citation.] They are derived from the
    common law or statutes under which discretion is conferred.’ [Citation.] To determine if
    a court abused its discretion, we must thus consider ‘the legal principles and policies that
    should have guided the court’s actions.’ ” 
    (Sargon, supra
    , 55 Cal.4th at p. 773.)
    The principles of law governing admission of expert testimony are well-settled.
    “ ‘California law permits a person with “special knowledge, skill, experience, training, or
    education” in a particular field to qualify as an expert witness . . . and to give testimony
    in the form of an opinion.” (People v. Vang (2011) 
    52 Cal. 4th 1038
    , 1044; Evid. Code,
    §§ 720, 801.) “ ‘Generally, the opinion of an expert is admissible when it is “[r]elated to
    a subject that is sufficiently beyond common experience that the opinion of an expert
    15
    would assist the trier of fact . . . .” ’ ” (Allgoewer v. City of Tracy (2012) 
    207 Cal. App. 4th 755
    , 761 (Allgoewer); see Evid. Code, § 801, subd. (a) [expert testimony
    must be “[r]elated to a subject that is sufficiently beyond common experience that the
    opinion of an expert would assist the trier of fact”].) However, “ ‘ “[w]here the jury is
    just as competent as the expert to consider and weigh the evidence and draw the
    necessary conclusions, then the need for expert testimony evaporates.” ’ ” 
    (Allgoewer, supra
    ,. at p. 762.) Expert testimony will be excluded “ ‘ “when it would add nothing at
    all to the jury’s common fund of information, i.e., when ‘the subject of inquiry is one of
    such common knowledge that men [and women] of ordinary education could reach a
    conclusion as intelligently as the witness.’ ” ’ ” (People v. Jones (2012) 
    54 Cal. 4th 1
    ,
    60.)
    Some topics are categorically off-limits to expert testimony. (See Evid. Code,
    § 801, subd. (b) [caveat to admissibility where “expert is precluded by law from using
    such matter as a basis for his opinion”], § 802 [expert may state basis for opinion “unless
    he is precluded by law from using such reasons or matter as a basis for his opinion”].)
    For example, juries are competent to decide such things as witness credibility (People v.
    Wells (2004) 
    118 Cal. App. 4th 179
    , 189), a defendant’s guilt or innocence (People v.
    Torres (1995) 
    33 Cal. App. 4th 37
    , 46), or whether a crime has been committed (id. at p
    47), without expert assistance in all circumstances. Similarly, topics such as the
    definition of a crime (id. at pp. 45–46), the meaning of a statute (id. at p. 46), or other
    matters of law even if disguised as opinions about ultimate facts (Benavidez v. San Jose
    Police Dept. (1999) 
    71 Cal. App. 4th 853
    , 865), always lie beyond the proper role of an
    expert.
    2.     Civil Cases Addressing Expert Testimony on Excessive Force
    Issues
    The use of excessive force by law enforcement officers is analyzed under the
    Fourth Amendment’s objective reasonableness requirement for a seizure of the person
    
    (Graham, supra
    , 490 U.S. at pp. 388, 394–395; Brown v. Ransweiler (2009) 
    171 Cal. App. 4th 516
    , 527 (Brown)), and usually arises in one of two contexts: (1)
    16
    defensively, as here, when an accused seeks to defend against a charge of resisting arrest
    or similar offense by contending the arrest was unlawful due to the officer’s use of
    excessive force, and (2) offensively, when a person who claims to have been the victim
    of excessive force by law enforcement sues for damages under 
    42 U.S. C
    . section 1983
    (section 1983), or similar state law remedy. The specific question of admissibility of
    expert testimony on use of force in the first of these situations has not been resolved in
    California. Rather, the few cases shedding any light on this question, in California and
    elsewhere, arise in the civil context, usually under section 1983. Because the rules of
    evidence governing expert testimony in California, in other states, and in the federal
    courts are broadly similar, at least insofar as is material here, it is worthwhile to preface
    our analysis of this issue of first impression with a review of the pertinent civil precedent
    decided by courts nationwide.
    Summing up the state of the law across the country, one commentator recently
    observed that, although some courts allow excessive force expert testimony, “a larger
    number of courts have held that it is not required or not admissible.” (Annot.,
    Requirement for, and Admissibility of, Expert Testimony to Determine Whether Use of
    Particular Amount of Force in Course of Making Arrest Was Unreasonable (2015) 
    95 A.L.R. 6th 641
    , 649; see 
    id. at §§
    3–10 [collecting cases].) Illustrative of the majority
    view, this commentator noted, is 
    Allgoewer, supra
    , 
    207 Cal. App. 4th 755
    , the leading
    California case to address expert testimony on issues of excessive force. Though not
    directly applicable here, Allgoewer serves as a helpful entry point to our analysis.
    In Allgoewer, two police officers visited the home of plaintiff Allgoewer to
    investigate a complaint from Allgoewer’s former wife that he was keeping the couple’s
    son in violation of a child custody order. 
    (Allgoewer, supra
    , 207 Cal.App.4th at p. 758.)
    Allgoewer became agitated while talking to the officers in his yard, and refused to drop a
    hand rake that he had been using. (Ibid.) The officers forced him to the ground, tased
    him twice, and wrenched his arms behind his back while arresting him, breaking his wrist
    and tearing muscles in his shoulder and bicep. (Id. at pp. 758–759.) In Allgoewer’s civil
    suit against the officers for excessive force, the defense argued that he was required to
    17
    present expert testimony, drawing an analogy to medical malpractice cases. (Id. at
    pp. 759, 762.) The trial court found the argument persuasive and granted a non-suit
    motion. (Id. at p. 760.) Reversing, the appellate court began with a brief discussion of
    
    Graham, supra
    , 
    490 U.S. 386
    , the leading United States Supreme Court excessive force
    case involving non-deadly force. “Under Graham, . . . the question in a case such as this
    is whether the amount of force the officers used in making the arrest was objectively
    unreasonable given the circumstances they faced.”5 
    (Allgoewer, supra
    , 207 Cal.App.4th
    at p. 763.) Finding no California precedent directly addressing “[w]hether expert
    testimony is necessary to establish that a particular amount of force was objectively
    unreasonable” (ibid.), the court canvassed pertinent out-of-state authority, focusing on
    three cases, Kopf v. Skyrm (4th Cir. 1993) 
    993 F.2d 374
    (Kopf), Thompson v. City of
    Chicago (7th Cir. 2006) 
    472 F.3d 444
    (Thompson), and Robinson v. City of West Allis
    (Wis. 2000) 
    619 N.W.2d 692
    (Robinson) 
    (Allgoewer, supra
    , at pp. 763–764). From these
    cases, the court distilled the following: “[E]xpert testimony can be admissible on the
    issue of reasonable force” [Kopf], but is “not always admissible” [Thompson], and is
    5
    In assessing reasonableness, the Graham test calls for consideration of at least
    three factors (which have come to be called the “Graham factors” in subsequent case law
    and academic commentary): (1) the severity of the offense for which the suspect was
    arrested, (2) the immediacy of the threat that the suspect posed to the officer or officers,
    and (3) whether the suspect was fleeing or actively resisting. 
    (Graham, supra
    , 490 U.S.
    at p. 396.) “The most important of these is whether the suspect posed an immediate
    threat to the officers or others, as measured objectively under the circumstances.”
    (Mendoza v. City of West Covina (2012) 
    206 Cal. App. 4th 702
    , 712 (Mendoza).) Other
    factors may be significant in a given case (Smith v. City of Hemet (9th Cir. 2005) 
    394 F.3d 689
    , 701), since the “proper application [of the Fourth Amendment’s reasonableness
    test] requires careful attention to the facts and circumstances of each particular case . . . .”
    
    (Graham, supra
    , 490 U.S. at p. 396.) Overall, however, the Court in Graham
    emphasized that the test of “ ‘reasonableness’ of a particular use of force must be judged
    from the perspective of a reasonable officer on the scene, rather than with the 20/20
    vision of hindsight,” for “[t]he calculus of reasonableness must embody allowance for the
    fact that police officers are often forced to make split-second judgments—in
    circumstances that are tense, uncertain, and rapidly evolving . . . .” 
    (Graham, supra
    , 490
    U.S. at pp. 396–397.)
    18
    certainly not “required in an excessive force case” [Robinson]. 
    (Allgoewer, supra
    , 207
    Cal.App.4th at p. 764, italics in original.)
    Notably, the precise legal question addressed in Allgoewer—whether expert
    testimony is required from the plaintiff in a civil excessive force case—turns on a
    standard that differs significantly from the standard governing whether such testimony is
    admissible. For expert testimony to be admissible, it is not necessary that the subject of
    the testimony lie wholly beyond the understanding of the average juror, but merely that,
    even if the average juror has some knowledge of the topic, the expert might improve
    upon or refine the jury’s common fund of information.6 In cases where expert testimony
    is required, by contrast, the witness must have a degree of specialized knowledge that is
    peculiarly within the province of experts.7 Of the three out-of-state cases Allgoewer
    mentions, only Robinson addressed the question of whether expert testimony is required.
    Finding persuasive the Wisconsin Supreme Court’s observation in Robinson that “ ‘[w]e
    cannot at once emphasize the jury’s responsibility for applying the standard of
    reasonableness and also claim that the issue is beyond the jury’s comprehension,’ ”
    Allgoewer rejected the argument that expert testimony is required in an excessive force
    case. “ ‘Requiring an expert as a prerequisite to a finding of use of excessive force,’ ” the
    court reasoned, “ ‘would essentially remove from the jury the task of applying standards
    of reasonableness and replace it with the task of evaluating the testimony of the parties’
    experts.’ ” 
    (Allgoewer, supra
    , 207 Cal.App.4th at p. 765.)
    6
    People v. Dejourney (2011) 
    192 Cal. App. 4th 1091
    , 1110 (“Because admissibility
    of expert opinion is a question of degree, and a jury need not be wholly ignorant of the
    subject matter under the statutory rule, exclusion is only necessary where the opinion
    would add nothing at all to the jury’s common fund of information.”).
    7
    Miller v. Los Angeles County Flood Control Dist. (1973) 
    8 Cal. 3d 689
    , 702 (“If
    the matter in issue is one within the knowledge of experts only and not within the
    common knowledge of laymen, it is necessary for the plaintiff to introduce expert opinion
    evidence in order to establish a prima facie case.”), italics in original; see 
    Allgoewer, supra
    , 207 Cal.App.4th at pages 761–762.
    19
    Allgoewer and Robinson both involved force that was primarily physical in nature
    without the use of weapons or special law enforcement tools. The officers in Allgoewer
    threw the arrestee to the ground and wrenched his arms behind his back 
    (Allgoewer, supra
    , 207 Cal.App.4th at pp. 758–759), and the officers in Robinson punched the
    arrestee and slammed his face and body to the ground 
    (Robinson, supra
    , 619 N.W.2d at
    p. 696). Having rejected the notion that there is any per se rule requiring expert
    testimony, the courts in both cases went further and determined there was no case-
    specific “need” for expert testimony on the facts presented. As the Wisconsin Supreme
    Court put it in Robinson, “there is no indication that the reasonableness of the officers’
    actions involves matters so complex as to necessitate an expert. One need not be an
    expert to determine whether a reasonable use of force in effectuating an arrest includes
    smashing an arrestee’s face to the ground or landing a punch to the side of his head. . . .
    The difficulty a jury will have with this case lies not in applying the reasonableness
    standard to the facts as it finds them but in untangling the disputed facts presented by the
    parties.” 
    (Robinson, supra
    , 619 N.W.2d at pp. 700–701.) This secondary inquiry into
    whether excessive force expertise was “needed” on the facts presented is roughly
    analogous to whether proffered expert testimony will add anything to the knowledge of
    the average juror, but because the root question in Allgoewer and Robinson—whether
    expert testimony should be mandatory versus whether it should be admissible—differs
    from the one presented here, Thompson and Kopf, the other two cases discussed in
    Allgoewer, are more directly relevant to this case. Both Thompson and Kopf address
    admissibility.
    In Thompson, two officers saw what they suspected was a drug buy take place
    between the driver of a parked black Mustang and a man who approached him. They
    tailed the Mustang for a few blocks and then tried to pull it over for a traffic stop. The
    Mustang at first pulled over, but then suddenly sped up and tried to get away, leading the
    officers and several others who joined them on a high-speed chase that ended with the
    Mustang crashing. Eventually, seven officers arrived at the scene of the crash, where the
    driver of the car, James Thompson, 6’ 2”, 330 pounds, got out of the car and began
    20
    aggressively resisting their efforts to arrest him, swinging at them with his fists.
    Thompson was tackled to the ground, and while on the ground face down, one officer,
    Officer Hespe, sat on his back and placed him in a choke-hold, while the other officers
    handcuffed him. The chokehold collapsed Thompson’s air passages, and he suffocated to
    death. 
    (Thompson, supra
    , 472 F.3d at pp. 447–448.) In the ensuing civil suit under
    section 1983 against the officers, only Officer Hespe remained as an individual defendant
    when the case went to trial, and the defense moved in limine prior to trial to exclude the
    testimony of two experts proffered by the plaintiffs. According to the plaintiffs’ proffer,
    the experts would have opined that Officer Hespe did not adhere to his training and used
    a chokehold in violation of his department’s use-of-force policy. (Id. at pp. 449–450.)
    The trial court granted the motion in limine, and excluded the testimony.
    Affirming that ruling on appeal, the Seventh Circuit Court of Appeals noted that, under
    Graham, “What constitutes ‘reasonableness’ with regard to an officer’s actions in
    apprehending a suspect under the Fourth Amendment is ‘ “not capable of precise
    definition or mechanical application” but “requires careful attention to the facts and
    circumstances of each particular case . . . .” ’ ” 
    (Thompson, supra
    , 472 F.3d at p. 454
    (quoting 
    Graham, supra
    , 490 U.S. at p. 396).) The court then looked to Whren v. United
    States (1996) 
    517 U.S. 806
    , 815–816, where the United States Supreme Court rejected
    the use of police manuals and standard procedures to evaluate what a “reasonable officer”
    would do under the Fourth Amendment in the context of a traffic stop. Summarizing
    Whren, Thompson observed that “police rules, practices and regulations vary from place
    to place and from time to time,” and as a result, “are an unreliable gauge by which to
    measure the objectivity and/or reasonableness of police conduct” under the Fourth
    Amendment. 
    (Thompson, supra
    , at p. 455.) Accordingly, Thompson concluded,
    “Introducing two experts to testify that Officer Hespe used excessive force would have
    induced the jurors to substitute their own independent conclusions for that of the
    experts.” (Id. at p. 458.)
    Kopf was another case involving the use of various forms of physical force, which
    included the use of a trained police dog. In that case, a man and a woman, Anthony
    21
    Casella and Tammy Obloy, were suspects in the robbery of a pizza parlor. A team of
    police officers chased them, at first by car, and then, eventually, on foot, catching up to
    them in an area behind a garage, where the suspects tried to hide in a narrow passageway
    between two buildings. The officers released a police dog into the passageway, where it
    mauled both Casella and Obloy, despite cries from Obloy not to let the dog attack her
    because she was pregnant. The officers eventually dragged the suspects out of the
    passageway, with the dog continuing to bite at Casella. They testified that, once Cassella
    was freed from the passageway, he lunged at them. In response, an officer struck Casella
    multiple times in the head with a flashlight until it broke, and then with a slapjack.
    Casella suffered multiple lacerations from the dog bites and permanent brain injury from
    the blows to his head. 
    (Kopf, supra
    , 993 F.2d at pp. 375–376.) At the trial of a
    subsequent section 1983 case brought by Cassella’s personal representative (he had since
    died in an unrelated incident), the officers testified that in making the arrests they simply
    followed their training. In rebuttal, the plaintiffs sought to offer the expert testimony of a
    use-of-force expert who proposed to testify that the officers, in fact, violated
    departmental use-of-force policy and did not follow their training. (Id. at pp. 376–377.)
    The trial court excluded the plaintiff’s expert, and on appeal a panel of the Fourth
    Circuit Court of Appeals reversed. 
    (Kopf, supra
    , 993 F.2d at p. 375.) The Court of
    Appeals faulted the trial court for applying what appeared to be “a blanket rule that
    expert testimony is generally inappropriate in excessive force cases . . . .” (Id. at p. 378.)
    “The facts of every case will determine whether expert testimony w[ill] assist the jury.
    Where force is reduced to its most primitive form—the bare hands—expert testimony
    might not be helpful. Add handcuffs, a gun, a slapjack, mace, or some other tool, and the
    jury may start to ask itself: what is mace? what is an officer’s training on using a gun?
    how much damage can a slapjack do? Answering these questions may often be assisted
    by expert testimony. [¶] A dog is a more specialized tool than a gun or slapjack. How to
    train a poodle to sit or roll over is not everyday knowledge and could be explained by an
    expert in a case where it was relevant. How to train and use a police dog are even more
    obscure skills.” (Id. at p. 379.) Looking with close scrutiny at each type of force used,
    22
    the court found it was an abuse of discretion not to allow expert testimony concerning the
    officers’ training and use of police dogs and slapjacks because these tools involved
    enough special knowledge to warrant expert explanation. (Ibid.)
    Hygh v. Jacobs (2d Cir. 1992) 
    961 F.2d 359
    (Hygh), another civil excessive force
    case involving physical blows to a suspect, is relevant here as well. There, in the course
    of an arrest for disorderly conduct, Officer Jacobs slugged William Hygh in the face,
    fracturing three cheek-bones. Jacobs claimed he hit Hygh with his fist in self defense.
    (Id. at p. 361.) At trial in a section 1983 case seeking damages for excessive use of force,
    Hygh presented a medical expert who opined, based on the extent of the injuries, that
    Jacobs struck Hygh with “a blunt instrument of some sort.” (Ibid.) Since Jacobs
    admitted he was carrying a flashlight that night, Hygh also presented a law enforcement
    expert who testified that if Jacobs used the flashlight to strike Hygh rather than a fist, the
    extent of force used was objectively unreasonable because the use of such a blunt
    instrument met the legal definition of “deadly physical force.” (Id. at pp. 361–362.) On
    appeal from a jury verdict in favor of plaintiff Hygh, the Second Circuit Court of Appeals
    held that it was error to permit the expert to address legal matters, even though he did not
    directly tell the jury how it should decide the case. “Even if a jury were not misled into
    adopting outright a legal conclusion proffered by an expert witness,” the court held, “the
    testimony would remain objectionable by communicating a legal standard—explicit or
    implicit—to the jury. [Citations.] Whereas an expert may be uniquely qualified by
    experience to assist the trier of fact, he is not qualified to compete with the judge in the
    function of instructing the jury.” (Id. at p. 364). In the end, however, the appellate court
    affirmed. After observing that the trial court had instructed the jury on the same matters
    Hygh’s expert addressed, and that the difference between the expert’s version of law and
    the trial court’s was “not substantial” (id. at p. 364), the appellate court found the law
    enforcement expert’s testimony was erroneously admitted, but was not prejudicial,
    although it did remark that the “question is close” (id. at pp. 364–365).
    While some of these cases are more directly applicable than others, each of them
    is to some degree instructive. Broadly speaking, Allgoewer, Robinson, Thompson and
    23
    Kopf all view the utility of expert testimony in civil excessive force cases through a
    common frame of reference. Within that frame, the correct analysis is case-by-case and
    very much dependent on the particular facts presented, but in general, where only bodily
    force is used, the less likely it will be that an excessive force expert will add something to
    the common store of knowledge that every jury brings to its task. Since the ultimate
    issue for a jury to decide under Graham is whether the challenged conduct is objectively
    reasonable, the training of particular officers—which focuses subjectively on how they
    were predisposed to handle the situation they faced—is, at best, only marginally relevant.
    What counts is whether a reasonable officer, faced with the same set of circumstances,
    would have chosen the same course of action. Hygh adds the refinement that, even where
    an expert does not address the ultimate issue for decision by a jury, legal guidance on
    what constitutes objectively reasonable conduct must come from the trial judge, not from
    the expert.
    3.     Analysis
    a.      The Threshold Issue of Form
    The Attorney General acknowledged at oral argument that expert testimony from
    the prosecution on the issue of excessive force is “unusual” on a section 69 charge. It is
    indeed unusual, and was here, both for the substance offered and the way in which it was
    presented. In the course of his testimony, Sergeant Walle opined at one point that, taking
    the officers’ version of events as true, Brown had engaged in “assaultive” conduct,
    justifying the force the officers used in response, but for the most part his testimony was
    presented as a general overview of the applicable law and the “defensive tactics” course
    that he teaches to all officers in the RPD. The purpose of this tutorial was never made
    clear to the jury, but the prosecutor did explain to the court—though not to the jury—that
    she was concerned jurors could “get the wrong impression” about the aggressive tactics
    these officers employed to subdue a fleeing 67-year-old: “[W]hen there’s a struggle,
    especially with more than one officer, juries can get the wrong impression that . . . they’re
    ganging up on him,” and when “there’s a knee strike to the ribs . . . which then is
    24
    followed by a punch, which is essentially a distraction blow, can seem [¶] . . . [¶]
    excessive. But they are trained to use . . . these . . . tactics to get someone under control.”
    The Evidence Code presupposes the presentation of expert testimony in the form
    of reasoned opinions.8 That has the salutary effect of ensuring some degree of logical
    rigor, which not only allows the foundation for an expert’s opinion to be properly
    screened for reliability (see 
    Sargon, supra
    , 55 Cal.4th at p. 769 [“[u]nder California law,
    trial courts have a substantial ‘gatekeeping’ responsibility” to screen expert testimony for
    admissibility]), but once past that threshold screen, helps keep its presentation to the jury
    focused on subject matter circumscribed by its rationale for admission.9 The form of
    8
    See Evidence Code section 801, subdivision (a) (“If a witness is testifying as an
    expert, his testimony in the form of an opinion is limited to such an opinion” as is
    “sufficiently beyond common experience that the opinion of an expert would assist the
    trier of fact”), italics added; Evidence Code section 801, subdivision (b) (expert
    testimony must be based on matter “that is of a type that reasonably may be relied upon
    by an expert in forming an opinion upon the subject to which his testimony relates”),
    italics added; Evidence Code section 802 (“A witness testifying in the form of an opinion
    may state on direct examination the reasons for his opinion and the matter . . . upon
    which it is based, unless he is precluded by law from using such reasons or matter as a
    basis for his opinion. The court in its discretion may require that a witness before
    testifying in the form of an opinion be first examined concerning the matter upon which
    his opinion is based.”), italics added.
    9
    A pair of federal cases, both from the Sixth Circuit Court of Appeals, illustrate
    the importance of ensuring at the “gatekeeping” stage that proposed testimony from a
    police practices expert is specifically focused on matters within the expert’s
    qualifications. In Berry v. City of Detroit (6th Cir. 1994) 
    25 F.3d 1342
    (Berry), the
    plaintiff in a section 1983 excessive force case presented a retired police officer witness
    with expertise in police “defensive tactics.” (Id. at p. 1349.) The trial court found the
    witness qualified to testify as an expert, and on the strength of his testimony about what
    he described as deficient use-of-force training and disciplinary practices, a jury awarded a
    large damage verdict. (Id. at pp. 1343–1344, 1348–1349.) Reversing, the Sixth Circuit
    Court of Appeals held the expert’s testimony should have been excluded as unreliable.
    (Id. at pp. 1348–1354.) “[T]here is no such ‘field’ as ‘police policies and practices.’ . . .
    [T]here was no foundation at all for discipline testimony, even though it would fall under
    the general label of ‘police policies and practices[,]’ . . . [a phrase that] is so broad as to
    be devoid of meaning. It is like declaring an attorney an expert in the ‘law.’ ” (Id, at
    p. 1352.) More recently, the Sixth Circuit, in another section 1983 excessive force case,
    25
    presentation here observed no such boundaries. Even assuming it was proper for the
    prosecution to present Sergeant Walle’s testimony in the form we see here—no objection
    having been interposed on that ground—the substance of the testimony should
    nevertheless have been excluded. Because Sergeant Walle’s testimony (i) added nothing
    to the common fund of information that any juror would have brought to the jury room,
    and (ii) inaccurately addressed the governing law, he, in essence, invited the jury to
    abdicate its duty to decide the issue of excessive force based on an erroneous
    understanding of the law. Brown’s motion in limine seeking exclusion of the testimony
    should therefore have been granted.
    b.     Specialized Knowledge
    For the jury to sort out what happened here, specialized knowledge was not
    required. Because these officers used “force . . . reduced to its most primitive form—the
    bare hands” 
    (Kopf, supra
    , 993 F.2d at p. 379), this was not a case in which the proper
    handling of some specialized law enforcement tool (e.g. a gun, a dog, a taser, mace,
    pepper spray) had to be explained. It may be to these officers’ credit that they chose to
    use only physical force, but an expert was not required to make that elementary point.
    Nor was it a matter of specialized knowledge that two officers are more effective than
    one; that a second officer may come to the aid of another officer who is having trouble
    subduing a suspect; or that, to gain control over a resisting suspect, law enforcement
    officers are permitted to use their hands, fists, knees, feet or other body parts. The
    question here was not whether two officers could join in the pursuit of Brown or use
    bodily force against him, but whether they went overboard when they caught him. On
    distinguished Berry, explaining, “We did not hold that an individual cannot ever testify as
    an expert about some aspect of police affairs. Rather, the holding in Berry reasoned that
    unqualified individuals could not broadly testify about an area in which they possessed
    no specialized knowledge.” (Champion v. Outlook Nashville, Inc. (6th Cir. 2004) 
    380 F.3d 893
    , 908 (Champion). Because the expert in Champion focused his testimony on a
    “discrete area of police practices about which he had specialized knowledge,” (id. at
    p. 909) the court found no abuse of discretion in the admission of the testimony of a
    police practices expert. (Id. at pp. 908–909.)
    26
    this crucial question of proportionality, technical jargon (“pain compliance,” “personal
    weapons,” “control techniques”) and truisms about the amount of force officers may use
    (enough to ensure that their target cannot engage them in “a fair fight”) add nothing to the
    everyday understanding anyone would bring to the jury room.
    In a different criminal context but one also raising the issue of the admissibility of
    expert testimony on matters for jury determination under a legal standard of objective
    reasonableness, the court excluded testimony from an expert in People v Czahara (1988)
    
    203 Cal. App. 3d 1468
    (Czahara). In that case, the defendant shot his ex-girlfriend and
    her new boyfriend, and was then convicted of multiple attempted murder convictions.
    (Id. at p. 1471.) Claiming that he reacted to provocation, the defendant called a
    psychiatrist as an expert witness who, according to an offer of proof, would have testified
    that “the ordinarily reasonable person in the same circumstances would also have acted in
    passion.” (Id. at p. 1476.) This testimony, the defendant argued, was relevant to the
    objective, reasonable person component of his heat of passion defense. (Id. at p. 1477.)
    Affirming the trial court’s exclusion of the testimony, the appellate court ruled that “the
    adequacy of provocation is not a subject sufficiently beyond common experience that the
    opinion of an expert would assist the trier of fact.” (Id. at p. 1478.)
    The Czahara court explained, “the reasonableness of [the defendant’s] reaction is
    left to the jurors precisely so that they may bring their common experience and their own
    values to bear on the question of whether the provocation partially excused the violence.
    . . . While courts have frequently held certain categories of provocation adequate or
    inadequate as a matter of law, the modern tendency is to leave the jury free to apply
    community norms to the question. [Citation.] [¶] Psychologists, psychiatrists or
    sociologists may have specialized empirical knowledge regarding the range of reactions
    to a given provocation, . . . [b]ut this information would not materially assist the jury in
    its task; the jury must determine not only if the reaction is ordinary but if it is reasonable
    . . . .” 
    (Czahara, supra
    , 203 Cal.App.3d at p. 1478.) The ultimate determination of
    reasonableness, the court held, “depends more on (perhaps unarticulated) community
    norms” than on any empirical knowledge the expert could have supplied. (Ibid.; see
    27
    Burton v. Sanner (2012) 
    207 Cal. App. 4th 12
    , 14 [expert “usurped the jury’s role” where
    “[t]he test of reasonableness” on an issue of self defense was “an objective one for the
    jury” and “it is just as competent as the expert to evaluate the evidence and draw
    conclusions”].)
    Similarly, here, it was important for a jury to apply a reasonableness standard
    using its common knowledge. Once the jury determined that some use of force was
    appropriate in subduing Brown, its task was to determine whether these officers
    overreacted to the circumstances. To guide that assessment, Graham lays down a broad
    test highlighting certain factors for consideration, all to be viewed from the standpoint of
    the officer in the field. (Martinez v. County of Los Angeles (1996) 
    47 Cal. App. 4th 334
    ,
    343.) At the end of the day, however, the “ ‘[t]he test of reasonableness under the Fourth
    Amendment is not capable of precise definition or mechanical application . . . .’ ”
    
    (Graham, supra
    , 490 U.S. at p. 396, quoting Bell v. Wolfish (1979) 
    441 U.S. 520
    , 559.) It
    is highly situational and fact-specific, and in applying the test, the jury’s task not only
    permitted but required it to apply its own independent sense of reasonableness, using
    whatever community norms jury members might bring to the issue.
    c.     Expert Testimony on the Law
    “There are limits to expert testimony, not the least of which is the prohibition
    against admission of an expert’s opinion on a question of law.” (Summers v. A.L. Gilbert
    Co. (1999) 
    69 Cal. App. 4th 1155
    , 1178.) Embedded in Sergeant Walle’s overview of his
    mandatory “defensive tactics” training course was an explanation of the governing law.
    At the start of Sergeant Walle’s examination, the prosecutor posed a series of direct
    questions about the law, asking him “what does the law state is a reason for an officer to
    use force?” and “[h]ow is reasonable force defined?” Sergeant Walle responded that the
    legal authority for an officer’s use of force is “835(a) of the Penal Code” and explained
    that all RPD officers are given training founded on Graham v. Connor.10
    10
    The Attorney General argues that Brown failed to preserve any specific
    objection to Sergeant Walle’s testimony about the law. But this is not a case in which the
    appeal raises “ ‘a wholly different basis of exclusion’ ” than the trial objections. (Cf.
    28
    Sergeant Walle then summarized his understanding of Graham for the jury, but
    provided a truncated explanation, partially mentioning only one of the three factors the
    Supreme Court held should be taken into account in assessing reasonableness—whether
    the suspect is actively resisting or fleeing—never mentioning that the test is an objective
    one, and repeatedly emphasizing “the law says you’re supposed to put yourself in the
    shoe[s] of an officer at the time of the incident . . . because it is fluid and ever
    changing[.]” The jury instructions in this case did not address Graham. As noted above,
    the court instructed the jury using CALCRIM No. 2670, which advised it that “A peace
    officer may use reasonable force to arrest or detain someone, to prevent escape, to
    overcome resistance, or in self-defense,” but beyond that, it gave no instruction
    explaining the criteria for the jury to use in distinguishing “reasonable” from “excessive”
    force. Sergeant Walle supplied the jury’s only legal guidance on this crucial issue, and
    the two “Graham factors” he omitted—the severity of the crime for which the suspect
    was being sought, and the immediacy of the threat the suspect posed—were both
    potentially important here.
    The Attorney General points out that Sergeant Walle discussed the law only
    briefly, by way of background explanation. The testimony may have been brief, but it
    was powerful. Clearly, the jury focused on it. Perhaps not surprisingly, since the jury
    had no other source of legal guidance on this key legal issue—by contrast to Hygh, where
    an expert merely echoed the trial court’s instructions—it asked for a read-back during
    deliberations of the “testimony of [Sergeant] Walle regarding training of police officers,
    specifically regarding compliance strikes and reasonable vs excessive force . . . i.e. need
    People v. Williams (1988) 
    44 Cal. 3d 883
    , 907, fn. 6.) Brown objected to Sergeant
    Walle’s testimony in its entirety, and in support of that objection he argued that Sergeant
    Walle’s testimony contained no specialized content and invaded the province of the jury.
    Because the prejudicial impact of admission of Sergeant Walle’s testimony over these
    objections—both of which were well taken—was bound up with his testimony on the
    law, the grounds for objection asserted by Brown were sufficient to “fairly inform the
    trial court . . . of the specific reason or reasons the objecting party believes the evidence
    should be excluded.” (People v. Partida (2005) 
    37 Cal. 4th 428
    , 435.)
    29
    his entire testimony other than his introduction.” (Italics added.) Thus, even though
    Sergeant Walle did not in terms advise the jury how to decide the ultimate issue, he did
    manage to provide it with a legal standard for decision, thereby vesting himself with
    authority as a source of legal knowledge. Summing up the problem with expert
    testimony of this sort in Hygh, the Second Circuit Court of Appeals explained: “ ‘The
    danger is that the jury may think that the ‘expert’ in the particular branch of the law
    knows more than the judge—surely an inadmissible inference in our system of law.’ ”
    
    (Hygh, supra
    , 961 F.2d at p. 364, quoting Marx & Co., Inc. v. Diners’ Club Inc. (2d Cir.
    1977) 
    550 F.2d 505
    , 512.)
    As in 
    Burton, supra
    , 
    207 Cal. App. 4th 12
    , which also involved a police expert’s
    testimony on use-of-force training (including such matters as “pain compliance” and the
    “use-of-force continuum”), “the court essentially allowed [Sergeant Walle] to instruct the
    jury on his view of applicable legal principles and standards, even though he is
    unqualified to do so . . . .” (Id. at p. 23.) Like his counterpart in Burton, Sergeant Walle
    “has impressive credentials as an educator and authority figure” with RPD. (Id. at p. 24.)
    Indeed, in addition to training other officers on “defensive tactics,” proper use of “pain
    compliance” techniques, and the like, Sergeant Walle was an investigator in the Internal
    Affairs Unit and currently sits on RPD’s Use of Force Board, where he evaluates the
    reasonableness of RPD officers’ actions on a day-to-day basis. In view of those
    credentials, the jury had every reason to look to him as a far better judge than they could
    be of the reasonableness of those officers’ tactics.
    The prosecutor was, of course, entitled to ensure the jury understood “there will
    virtually always be a range of conduct that is reasonable” 
    (Brown, supra
    , 171
    Cal.App.4th at p. 537, italics in original), and that “ ‘ “[t]he Supreme Court’s definition
    of reasonableness is . . . “comparatively generous to the police. . . .’ ” [Citation.]’ ” (Id.
    at p. 528, quoting Munoz v. City of Union City (2004) 
    120 Cal. App. 4th 1077
    , 1103
    (Munoz), disapproved on other grounds in Hayes v. County of San Diego (2013) 
    57 Cal. 4th 622
    ), but if she wished to emphasize these points, she was fully entitled to do so
    by requesting a special jury instruction on the Graham factors and then elaborating on
    30
    that instruction in closing argument.11 While counsel is expected to present argument
    anchored in the law, fairly read, the fact that an expert does so, and does so based on an
    inaccurate rendition of the law, is an indication he has improperly stepped outside his role
    as adjunct to the fact finder. (See 
    Burton, supra
    , 207 Cal.App.4th at p. 24 [reversing and
    finding miscarriage of justice where an expert tried to do what an advocate could not and
    improperly testified that “he turns down most court cases offered to him, and he only
    takes a case if he ‘wholeheartedly and truly believe[s] in the case itself’ ”].)12
    d.     Invasion of the Province of the Jury
    Emphasizing that Officer Walle did not opine on the ultimate issue of
    reasonableness, the Attorney General points out that “it was still up to the jury to decide
    whether the officers’ actions in this case conformed to their training” and that “[t]he
    jury’s verdict suggests . . . it found that the officers’ use of force was consistent with their
    training.” Her framing of the issue is telling. Putting to one side that the defense never
    contested the officers were properly trained,13 this line of argument highlights why the
    11
    
    Munoz, supra
    , 120 Cal. App.4th at page 1110 (“The quotation directing the jury
    that the test of reasonableness ‘is not one of 20/20 hindsight, but one which necessarily
    allows for the fact that police officers are often forced to make split-second decisions in
    circumstances that are tense, uncertain, and rapidly evolving with the amount of force
    which is necessary’ was taken directly from case law [citation] and is a correct statement
    of law. Although not appropriate as an instruction from the court, there was nothing
    wrong with these statements as part of closing argument.”).
    12
    This illustrates how the open-ended form of much of Sergeant Walle’s
    testimony created other problems. Sergeant Walle obviously was not and could never
    have been qualified as an expert in the law. But because his testimony was not presented
    in a way that ensured he would address only a “discrete area of police practices about
    which he had specialized knowledge” 
    (Champion, supra
    , 380 F.3d at p. 909; see fn. 9,
    ante), he managed to roam beyond his demonstrated area of expertise by folding his
    testimony on the law into his training course tutorial.
    13
    In closing argument, Brown’s contention was not that Officers Moody and
    Ricchiuto were poorly trained or incompetent, but that they made a mistake when they
    perceived him as a threat, that they overreacted to the situation and beat him up in
    retaliation for his defiance, and that their testimony about him swinging at them was
    fabricated to cover up their mistake.
    31
    testimony should have been excluded, not why it should have been admitted. It concedes
    the thrust of Brown’s argument for exclusion—that the true purpose of Sergeant Walle’s
    testimony was not to educate the jury about control techniques they would otherwise
    have had difficulty understanding, but instead to suggest that, because Officers Ricchiuto
    and Moody conducted themselves “by the book,” in accordance with legally sanctioned
    training, what they did was therefore within the bounds of the law. In effect, Brown
    argues, Sergeant Walle’s testimony was an invitation to avoid the question of excessive
    force altogether by conflating it with whether the officers did as they were trained to do.
    He is correct, in our view.
    The Attorney General also contends that the training testimony could have cut
    both ways, since “if the jury found that the officers’ actions were inconsistent with their
    training it would tend to support the argument that the force used was unreasonable.”
    But the idea that RPD’s training regimen can serve as a valid Fourth Amendment
    benchmark for reasonableness—available for either side to argue—rests on the premise
    that the officers’ training itself is reasonable. We have no reason to doubt that premise as
    a matter of law enforcement policy, but by placing the issue before the jury, the court
    opened up a line of inquiry that was potentially distracting and confusing.14 As Brown’s
    counsel put the issue in support of his motion in limine, “Whether the officers are trained
    14
    Brown points out that in the wake of a series of high profile controversies
    involving use of force by police officers in different parts of the country, a number of law
    enforcement agencies have adopted reforms to their use-of-force training. (See Apuzzo,
    Police Rethink Long Tradition on Using Force, N.Y. Times (May 5, 2015) p. A1; see also
    Michelle E. McStravick, The Shocking Truth: Law Enforcement’s Use and Abuse of
    Tasers and the Need for Reform (2011) 56 Vill. L. Rev. 363, 384–385 [pointing out that
    the Federal Law Enforcement Training Center (FLETC), the national training institute
    that developed the use-of-force continuum, has made clear that, because of the formulaic
    nature of the continuum, it “directly conflicts with” Graham’s conception that
    “ ‘reasonableness under the Fourth Amendment is not capable of precise definition or
    mechanical application’ ”, and as a result, FLETC has “done away with the use-of-force
    continuum” in its own training materials, although many law enforcement agencies
    around the country still use some form of the continuum in their training programs.].)
    32
    this way or not doesn’t necessarily make physical action reasonable.” Reasonableness
    for Fourth Amendment purposes was for the jury to decide based on the facts of Brown’s
    encounter with Officers Moody and Ricchiuto, not by using the officers’ training as a
    proxy for it. Presented with the same line of argument the Attorney General makes here,
    the Thompson court explained: “It may be that” adherence to local training rules might be
    of interest to those “making discipline, promotion or salary decisions,” but “that
    information was immaterial” in this trial. 
    (Thompson, supra
    , 472 F.3d at p. 455.)
    Because introducing an expert to address the issue of training “induced the jurors to
    substitute their own independent conclusions for that of the expert[]” 
    (Thompson, supra
    ,
    472 F.3d at p. 458), the court excluded testimony about officer training as more time
    consumptive and confusing than probative under Federal Rule of Evidence 403 (the
    federal counterpart to Evidence Code section 352) (id. at p. 453).
    The balance of probative value versus potential to confuse and distract illustrates a
    key difference between this case and the civil cases addressing the admissibility of
    testimony from a police training expert on excessive force issues. In general, the scope
    of relevant subject matter implicating issues of excessive force tends to be broader in
    civil cases than it is in criminal cases, and as a result, the probative value of testimony
    from an excessive force expert is typically stronger there. In section 1983 cases, for
    example, the contested issues may include an officer’s good faith as part of a qualified
    immunity defense,15 agency liability based on alleged excessive use of force pursuant to
    official policy,16 or supervisorial liability under a deliberate indifference theory.17 And in
    15
    Venegas v. County of Los Angeles (2004) 
    32 Cal. 4th 820
    , 839–840 (recognizing
    availability of qualified immunity defense to section 1983 claims asserted in the
    California courts); see 
    Mendoza, supra
    , 206 Cal.App.4th at page 711; Martinez v. County
    of Los Angeles (1996) 
    47 Cal. App. 4th 334
    , 342 (Martinez).
    16
    Blankenhorn v. City of Orange (9th Cir. 2007) 
    485 F.3d 463
    , 484 (Blankenhorn)
    (“Blankenhorn seeks to hold the City liable for the arresting officers’ alleged use of
    excessive force. The City may be held liable under section 1983 if its deliberate policy
    caused the constitutional violation alleged.”); see Monell v. New York City Dept. of Social
    Services (1978) 
    436 U.S. 658
    , 694 (agency liability under section 1983 where misconduct
    of individual officers was undertaken pursuant to official policy).
    33
    connection with state law tort claims, which frequently accompany section 1983 claims,
    the scope of an officer’s duty to the suspect or others18 or the statutory defenses of
    justification or immunity19 may also be at issue. Because the Fourth Amendment focuses
    more narrowly on the moment force is used than state tort law does (Hayes v. County of
    San 
    Diego, supra
    , 57 Cal.4th at p. 638), placing less emphasis on matters preceding that
    instant than tort law does, officer training and tactics can potentially be relevant for
    purposes of tort liability, where it is not for Fourth Amendment purposes.
    Here, the perceptions of Officers Moody and Ricchiuto as to the circumstances
    they faced on the evening of November 14, 2011 were certainly in issue—and of course
    they testified at length about what they were seeing and thinking—but those perceptions
    and the officers’ responses to the situation were to be evaluated in objective terms. While
    RPD’s programmatic approach to training might have been relevant had Brown attacked
    the credibility of these two officers with charges of rogue conduct in violation of RPD
    rules or policy, the prosecution never argued that expert testimony was needed because
    Brown opened the door to it. Nor was there any basis to do so. Brown’s defense, which
    17
    
    Blankenhorn, supra
    , 485 F.3d at page 485 (“Blankenhorn also seeks to hold
    Chief Romero liable for Nguyen’s alleged use of excessive force in punching
    Blankenhorn during the arrest. Chief Romero can be held liable in his individual
    capacity ‘ “for his own culpable action or inaction in the training, supervision, or control
    of his subordinates; for his acquiescence in the constitutional deprivation[;] or for
    conduct that showed a reckless or callous indifference to the rights of others.” ’ ”); see
    Canton v. Harris (1989) 
    489 U.S. 378
    (respondeat superior liability under section 1983
    where supervisor was deliberately indifferent to misconduct of individual officers under
    him).
    18
    Calatayud v. State of California (1998) 
    18 Cal. 4th 1057
    (officers brandishing
    shotguns while making an arrest owed no duty of care to fellow officer who was shot
    when one of the shotguns accidentally discharged).
    19
    
    Martinez, supra
    , 47 Cal.App.4th at page 349 & footnote 8 (defenses of official
    justification under Pen. Code, § 196 and official immunity under Gov. Code, § 820.2
    apply to wrongful death claim in civil excessive force suit against officers for shooting
    knife-wielding man who was high on PCP).
    34
    focused on the “lawful performance” element of the section 69 charge, framed the
    excessive force issue in purely Fourth Amendment terms. According to him, the
    applicable rule of conduct was constitutional, not one found in a policy manual or in the
    teachings of Sergeant Walle. As the court observed in Thompson, “police rules, practices
    and regulations vary from place to place and from time to time,” and as a result, “are an
    unreliable gauge by which to measure the objectivity and/or reasonableness of police
    conduct” under the Fourth Amendment. 
    (Thompson, supra
    , 472 F.3d at p. 455.)
    e.      Prejudice
    The erroneous admission of Sergeant Walle’s testimony compounded the
    prejudicial effect of the court’s failure to instruct on the lesser included offense of simple
    assault. The nub of the matter is that the jury could have found that this 67-year-old’s
    behavior in struggling against arrest and swinging at these two officers, if that is what he
    did, was never a genuine threat to them. Had the jury undertaken a close examination of
    the facts, as the reasonableness standard under Graham required it to do—without the
    temptation to short-circuit its decisionmaking process by concluding that the officers
    simply did as they were trained to do—Brown had a materially stronger case for a more
    favorable outcome on the section 69 charge than he was able to muster with Sergeant
    Walle’s testimony in the mix. Brown suggests that the distorting impact of Sergeant
    Walle’s testimony so impaired the jury’s independence as to violate his constitutional
    rights to a fair and impartial jury and to due process, justifying reversal under Chapman
    v. California (1967) 
    386 U.S. 18
    , but we see no need for such strong medicine. It
    suffices to say that, without the distraction of Sergeant Walle’s testimony, there was a
    reasonable probability that he would have obtained a better result on the section 69
    charge than he did. (People v. Watson (1956) 
    46 Cal. 2d 818
    , 836.)
    The law provides a generous mantle of protection to law enforcement officers
    accused of excessive force, but also contemplates that, where such questions are serious
    enough to be tried, juries will have a vital role in deciding what constitutes objectively
    reasonable force, bringing with them their independent sense of the values of the
    community in which they sit. Because Sergeant Walle’s testimony failed to meet two
    35
    fundamental requisites for expert testimony—that the expert must add something to the
    common fund of knowledge the jury brings to its task, and that the expert must not usurp
    the court’s role in giving the jury guidance on the law—the admission of his testimony
    not only undercut the jury’s ability to perform this vital role, but prejudiced Brown’s
    ability to mount a defense to the section 69 charge. 20
    IV.
    CONCLUSION AND DISPOSITION
    The judgment is affirmed with the exception of Brown’s conviction for violating
    section 69, which is conditionally reversed pursuant to the procedure outlined in People
    v. 
    Hayes, supra
    , 142 Cal.App.4th at page 184. If, after the filing of the remittitur in the
    trial court, the prosecutor does not retry Brown on the charged offense within the time
    limit of Penal Code section 1382, subdivision (a)(2), the trial court shall proceed as if the
    remittitur constituted a modification of the judgment to reflect a conviction of the lesser
    included offense of simple assault in violation of Penal Code section 240, and shall
    resentence Brown accordingly.
    20
    Though the question is a close one, if the jury had been instructed on the lesser
    included offense of simple assault and had returned a guilty verdict on that count, we
    would not have reached the same conclusion as to the assault conviction. Because the
    section 69 element of lawful performance of duty is not an element of assault, the
    prejudice analysis would have been quite different. The issue of excessive force was
    potentially relevant to assault, but in a different way than it was to the section 69 charge.
    There is no evidence in the record to support a defense to assault that, in response to
    unreasonable or excessive force by the officers, Brown used a “degree of force” that he
    “actually believe[d]” was reasonably necessary to protect himself. (CALCRIM No.
    2670.) Brown may have flailed reflexively at the officers, but he did not testify that he
    was trying to defend himself. Thus, we conclude there is no reasonable likelihood of
    outright acquittal for his conduct in the fracas leading to his arrest. As Brown’s counsel
    argued in his opening brief, the scenario in which the jury found that Brown swung at the
    officers would support a conviction for “simple assault rather than forcible resistance to
    lawful police conduct under section 69. That view of the facts—i.e., that there was
    improper or excessive use of force on both sides—was frankly the most plausible
    interpretation of the evidence.”
    36
    _________________________
    Streeter, J.
    I concur:
    _________________________
    Rivera, J.
    A141172/People v. Brown
    37
    Concurring opinion of Ruvolo, P. J.
    I concur with the majority that the conviction for resisting an officer in the
    performance of lawful duties (Pen. Code, § 69) must be reversed because the trial court
    failed to instruct the jury on the lesser included offense of simple assault (Pen. Code,
    § 240), and there exists a reasonable probability that a different result would have
    occurred had the jury been given the omitted instruction.
    Because this conviction must be reversed on this principal ground, there is no need
    to discuss the issue of the alleged erroneous admission of expert testimony posited as an
    alternative ground for reversal, let alone publish a discursive opinion on this legally and
    factually complex subject. Indeed, Brown’s appellate counsel agreed at oral argument
    that if the Penal Code section 69 conviction were to be reversed based on the failure to
    instruct on the lesser offense of simple assault, there was no need to decide the alternative
    evidentiary ground for reversal.
    ___________________________________
    RUVOLO, P. J.
    A141172, People v. Brown
    1
    People v. Brown (A141172)
    Trial Court:                            Contra Costa County Superior Court
    Trial Judge:                            Hon. Mary Ann O’Malley
    Counsel for Defendant and Appellant:    Jonathan Soglin, Executive Director
    J. Bradley O’Connell, Assistant Director
    First District Appellate Project
    Counsel for Plaintiff and Respondent:   Kamala D. Harris
    Attorney General of California
    Jeffrey M. Laurence
    Acting Senior Assistant Attorney General
    Gregg E. Zywicke
    Deputy Attorney General
    Bruce M. Slavin
    Deputy Attorney General
    2