George James Trepal v. Secretary, Florida Department of Corrections ( 2012 )


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  •                                                                       [PUBLISH]
    IN THE UNITED STATES COURT OF APPEALS
    FILED
    FOR THE ELEVENTH CIRCUIT                  U.S. COURT OF APPEALS
    ________________________                   ELEVENTH CIRCUIT
    June 19, 2012
    No. 10-15306                             JOHN LEY
    CLERK
    ________________________
    D.C. Docket No. 8:05-cv-01527-RAL-TBM
    GEORGE JAMES TREPAL,
    llllllllllllllllllllllllllllllllllllllllPetitioner-Appellant,
    versus
    SECRETARY, FLORIDA DEPARTMENT OF CORRECTIONS,
    llllllllllllllllllllllllllllllllllllllllRespondent-Appellee.
    ________________________
    Appeal from the United States District Court
    for the Middle District of Florida
    ________________________
    (June 19, 2012)
    Before CARNES, HULL and PRYOR, Circuit Judges.
    HULL, Circuit Judge:
    Florida death row inmate George James Trepal appeals the district court’s
    denial of his 28 U.S.C. § 2254 petition for a writ of habeas corpus. After review
    and oral argument, we affirm.
    I. BACKGROUND
    A.     Overview
    In 1991, a Florida jury convicted Trepal, a sophisticated chemist and Mensa
    member,1 of murdering his neighbor Peggy Carr and attempting to murder six
    other members of Carr’s family. Trepal poisoned the victims by adding the toxic
    element thallium to bottles of Coca-Cola in the Carrs’ home.
    Trepal’s trial lasted a month, with more than 70 witnesses together
    providing overwhelming evidence of Trepal’s guilt. For example, several
    independent witnesses chronicled Trepal’s long-running conflicts with and
    animosity toward the Carr family. Evidence established Trepal’s extensive
    knowledge of chemistry, as well as his possession of chemistry laboratory
    equipment, a number of toxic chemicals, and a homemade journal on poisons and
    poison detection in human organs. Finally, multiple experts uniformly testified
    that (1) the victims were poisoned by thallium, (2) thallium was found in both the
    empty and unopened Coca-Cola bottles in the victims’ home, and (3) thallium was
    1
    Mensa is a society of persons aged 14 and older who are in the top 2% of intelligence, as
    shown by test scores.
    2
    found in a brown bottle in Trepal’s garage. Thallium is a heavy metallic element
    that is both rare and toxic to humans. When dissolved, it is odorless and tasteless.
    A lethal dose of thallium is approximately 14 milligrams per kilogram of body
    weight, which for an average person is around 1 gram of thallium.
    Trepal’s case would be long over but for the fact that in 1997, six years after
    Trepal’s trial, the Office of the Inspector General of the United States Department
    of Justice (“OIG”) issued a report (the “OIG Report”) that was critical of certain
    work performed by Roger Martz, a Special Agent in the Chemistry-Toxicology
    Unit of the FBI Laboratory, who testified against Trepal. After other witnesses
    had established independently that thallium was found in Trepal’s garage and was
    put in Coca-Cola bottles to poison the victims, Agent Martz went further and tried
    to identify the particular chemical form of thallium that was found in Trepal’s
    garage and in three unopened Coca-Cola bottles in the victims’ home.
    Trepal filed a state postconviction motion alleging that certain parts of
    Martz’s trial testimony were false and thus Trepal was entitled to a new trial under
    Giglio v. United States, 
    405 U.S. 150
    , 
    92 S. Ct. 763
    (1972). The state court denied
    Trepal’s motion, finding that although some of Martz’s trial testimony was false, it
    did not prejudice Trepal enough to warrant a new trial, given the strength of the
    unchallenged portions of Martz’s testimony, other experts’ unchallenged
    3
    testimony, and all the other trial evidence of Trepal’s guilt. The Florida Supreme
    Court affirmed.
    Trepal filed his § 2254 petition, which the district court denied. A
    certificate of appealability (“COA”) was granted on Trepal’s Giglio claim. As
    explained later, this case presents many thorny issues about Trepal’s Giglio claim,
    such as the appropriate level of deference due the Florida Supreme Court’s denial
    of the claim, whether Martz’s testimony was false, whether Martz’s testimony can
    be imputed to the state prosecutor, and whether any false testimony was material
    under Giglio. Although we identify and discuss the issues to some extent, we
    ultimately need not decide them because even assuming arguendo that Trepal has
    shown a Giglio error, Trepal has not suffered the requisite actual prejudice and
    thus any Giglio error was harmless. To show why Trepal was not prejudiced, we
    outline in depth the evidence presented at trial and in state postconviction
    proceedings.
    B.     The Poisonings
    Trepal and his wife, Dr. Diana Carr, lived in Alturas, Florida, on property
    adjoining the home of victim Peggy Carr and her husband Parearlyn “Pye” Carr.2
    2
    Dr. Carr, a medical doctor, is no relation to Pye or Peggy Carr and their family. When
    we refer to the “Carr family,” we mean Pye and Peggy Carr and their relatives living on their
    property (whether or not those relatives bear the surname Carr), not Trepal’s wife or any of her
    4
    The two homes—Pye Carr’s and Trepal’s—were located amid orange groves and
    were very isolated. The next nearest neighbors were about a quarter-mile away.
    In June 1988, Pye Carr received an anonymous letter stating, “You and all
    your so-called family have two weeks to move out of Florida forever or else you
    will all die. This is no joke.” The letter was postmarked in nearby Bartow,
    Florida. Even though Pye’s home was in Alturas, the letter correctly listed Pye’s
    mailing address as being in Bartow, Florida. Pye’s and Trepal’s homes, both in
    Alturas, had Bartow mailing addresses because they got their mail on the Bartow
    post office route. Trepal would know this fact.
    On October 23, 1988, Peggy Carr began to show symptoms of an unknown
    illness, including nausea, pain in her chest and extremities, and difficulty
    breathing. She was admitted to Bartow Memorial Hospital the next day and stayed
    for three days. Back at home, Peggy’s symptoms worsened, and the children in
    the Carr home, Travis and Duane, began to show similar symptoms. On October
    30, 1988, Peggy, Travis, and Duane were admitted to Winter Haven Hospital.3
    relatives. To avoid confusion, we will refer to Dr. Carr as “Trepal’s wife.”
    3
    Peggy Carr and her teenaged son Duane Dubberly moved into Pye’s home after Peggy
    and Pye’s March 1988 wedding. Pye’s teenaged son, Travis Carr, lived in the home as well.
    5
    Treating neurologist Dr. Richard Hostler suspected thallium poisoning.4
    Within 24 hours, lab tests confirmed the presence of thallium in Peggy’s tissues.
    Despite treatment, Peggy Carr’s condition deteriorated, and within a week
    she lapsed into a coma from which she never awoke. She died on March 3, 1989.
    Duane remained hospitalized for two months and Travis for six months, but
    both eventually recovered. Tests revealed the presence of thallium not only in
    Travis and Duane, but also in Pye, his daughter Gelena, and his granddaughter
    Kasey, who also lived with Pye and Peggy.5
    C.     The Investigation
    Following the thallium poisoning diagnosis, the Polk County Sheriff’s
    Office and other governmental agencies searched for the source of the Carrs’
    exposure. Representatives of the Polk County Health Department, the Florida
    Department of Health and Rehabilitative Services (“HRS”), and the EPA searched
    4
    Pure thallium metal is not absorbed appreciably into the human body. However, there
    are a number of thallium salts (including thallium nitrate) that are water soluble. When
    dissolved, thallium forms an ion that, in human tissues, interferes with the body’s ability to use
    oxygen and generate energy.
    Thallium is used in certain manufacturing processes and in chemical laboratories, but it is
    not commonly available to the public. Thallium was used as an ingredient in rodenticides and
    pesticides in the United States until 1972, when the Environmental Protection Agency (“EPA”)
    banned its use in such products.
    5
    In March 1988, Pye converted a detached garage on his property into an apartment for
    his daughters, Tammy Carr and Gelena Bell, and Pye’s two-year old granddaughter, Kasey Bell.
    The residents of the apartment spent time in the “main” house, too.
    6
    the Carrs’ home.6
    At the Carrs’ home, investigators recovered an 8-pack of 16-ounce glass
    Coca-Cola bottles from the kitchen. Three bottles were full and four were empty.7
    The HRS and FBI Laboratories tested and found thallium in the three full bottles
    and thallium residue in the four empty bottles. The bottle caps from the three full
    bottles showed evidence of having been removed by a small tool and then placed
    back onto the bottles with a press or capping device. The investigation became a
    criminal one.
    In December 1988, investigators interviewed Trepal. When asked why
    anyone would want to poison the Carrs, Trepal said that perhaps someone wanted
    them to move out of their home. Investigators found Trepal’s response eerily
    similar to the threatening letter. Police later learned Trepal had a college degree in
    chemistry and in the 1970s was the chemist of a methamphetamine laboratory, for
    which he served two and a half years in federal prison. Local police began an
    undercover investigation of Trepal that lasted more than a year.
    On December 12, 1989, investigators searched Trepal’s home. They found
    a small brown bottle in the drawer of a workbench in his garage. The bottle
    6
    Local officials searched Peggy and Pye’s places of employment and found no thallium.
    7
    The eighth bottle consisted of broken pieces of glass.
    7
    contained a white powder that was tested and found to contain thallium.
    Trepal was arrested. On April 5, 1990, Trepal was indicted on one count of
    first-degree murder, six counts of attempted first-degree murder, seven counts of
    poisoning food or water, and one count of tampering with a consumer product.
    D.    Trial Evidence
    Trepal’s trial ran from January 7 to February 7, 1991. In the guilt phase, the
    State called more than 70 witnesses. Trepal’s three attorneys—J. Wofford
    Stidham, Jonathan Stidham, and Dabney Conner—called no witnesses, relying on
    the evidence elicited during cross-examination.
    Below we set forth in more detail the trial evidence by which the State
    connected Trepal to the Carr poisonings, divided into these topics: (1) Trepal’s
    suspicious police interview and the ensuing undercover investigation of Trepal,
    including the “Mensa murder weekend” event Trepal hosted; (2) the searches of
    Trepal’s homes, in which police discovered Trepal’s chemistry equipment, poison
    journal, poisonous chemicals, and the bottle of thallium; (3) Trepal’s chemistry
    and criminal background; (4) Trepal’s history of animosity toward the Carrs; (5)
    Florida HRS’s testing of the empty Coca-Cola bottles; (6) expert Havekost’s
    testing at the FBI Lab; (7) Martz’s testimony; and (8) testing by the Coca-Cola
    corporate laboratory.
    8
    1.     Trepal’s Suspicious Interview and Ensuing Undercover Investigation
    Detective Ernest Mincey of the Polk County Sheriff’s Office led the
    investigation and the interview of Trepal that put him on the police’s radar. In his
    interview, which took place on December 22, 1988, Trepal looked very nervous.
    Trepal told Detective Mincey and FBI Agent Brad Brekke that he was a self-
    employed computer programmer and technical writer and he knew nothing of
    thallium.
    When asked why someone might want to poison the Carr family, Trepal said
    perhaps someone wanted them to move out of their house, which, Trepal noted,
    the Carrs had done. Mincey found this response suspicious because it was
    different from those given by the more than 50 people Mincey had already
    interviewed and, as noted earlier, it was “almost identical” to the threatening letter.
    In April 1989, an article in the local newspaper advertised upcoming events
    for the Mensa organization, of which Trepal and his wife were members. The
    article discussed an upcoming “Mensa murder weekend” role-playing event that
    Trepal and his wife were hosting. Susan Goreck, a Special Agent with the Polk
    County Sheriff’s Department, began an undercover investigation of Trepal by
    attending the event under the assumed name “Sherry Guin.”
    The Mensa murder weekend was held at a local hotel. There were four
    9
    “murders” acted out during the weekend, which the participants, while acting out
    their roles, tried to solve. The story concerned voodoo. The murders were very
    sophisticated, and each of the four was preceded by the victim receiving a
    threatening note. Trepal’s wife wrote the murder scenarios with Trepal’s help. In
    particular, Trepal himself wrote a booklet given to participants during the
    weekend that discussed, among other things, poisoning and threats by neighbors.
    It stated:
    Few voodooists believe they can be killed by psychic means, but no one
    doubts that he can be poisoned. When a death threat appears on the
    doorstep, prudent people throw out all their food and watch what they
    eat. Hardly anyone dies from magic. Most items on the doorstep are
    just a neighbor’s way of saying, “I don’t like you. Move or else.”
    During the weekend, Trepal told Goreck that he and his wife were planning
    to move and that Trepal might be selling his Alturas home. Goreck told Trepal
    she would like to look at Trepal’s home if it were for sale.
    A few days after the Mensa murder weekend, Agent Goreck, as Sherry
    Guin, went to Trepal’s home, ostensibly about buying it. Goreck visited Trepal
    several more times in May and June 1989. Goreck became friends with Trepal and
    his wife and learned, among other things, that Trepal was very interested in botany
    10
    and knew about poisonous plants.8
    In November 1989, Trepal and his wife moved to Sebring, Florida. From
    December 1989 to January 1990, Goreck rented Trepal’s home in Alturas.
    2.      Searches of Trepal’s Homes and Discovery of Thallium Bottle
    While Goreck was renting Trepal’s house in Alturas, she and other law
    enforcement officers searched it. FBI Agent Brekke found a brown bottle inside
    the drawer of a workbench in Trepal’s detached garage. Agent Brekke uncapped
    the bottle and saw residue inside it. Goreck sent the bottle to the FBI Lab for
    analysis. The FBI Lab informed Goreck that the bottle contained thallium I
    nitrate.9
    Police also searched Trepal’s new home in Sebring, Florida. Police found
    chemistry books, including: (1) The Merck Index of Chemicals and Drugs; (2) the
    Handbook of Chemistry and Physics, which contained chemical information on
    8
    In January 1990, Goreck met with Trepal and brought up the Carr poisonings. Goreck
    testified that Trepal was usually very talkative, but was quiet and thoughtful during this
    conversation. Similarly, Patricia Boatright, who was a friend and confidante of Trepal, testified
    she asked Trepal about the poisonings and he “didn’t meet [her] eyes, and the subject was then
    dropped.” For some weeks afterward, there “was a strained quality” to Boatright’s relationship
    with Trepal, and she never discussed the poisonings again because “[i]t always just fell like a
    thud and the subject was changed.”
    9
    Two forms of thallium nitrate exist: thallium I nitrate and thallium III nitrate. The two
    forms of thallium nitrate have different chemical structures and properties, though both are toxic
    to humans.
    11
    thallium; and (3) the Fire Protection Guide on Hazardous Materials, which
    contained a section on thallium compounds. Police also seized from Trepal’s
    home: (1) a pamphlet written by Trepal called “Chemistry for the Complete Idiot,
    Practical Guide to all Chemistry” with pictures and index; (2) “many, many”
    chemicals, plus chemistry-related glassware and equipment; and (3) a homemade
    journal described as “a general poison guide.”
    Trepal’s journal included photocopied pages from a book entitled, Poison
    Detection in Human Organs. One of the photocopied pages included a discussion
    of thallium. The journal was tested for fingerprints and was found to have
    Trepal’s prints on it. Trepal’s wife’s prints were not found on the journal.
    Trepal’s journal also contained photocopied pages from another book with a
    section entitled, “Death by Poison Synopsis.” One page from the journal, which
    was read to the jury, stated that “Determining whether a person died as a result of
    natural illness or as a result of poisoning is one of the most difficult types of
    investigation both for the officer and for the medical expert.” The page described
    the process by which one tries to determine if someone has been poisoned. The
    next page in the journal stated, among other things, “The presence of any one
    poison is so difficult to ascertain that it may be undetected unless the [medical]
    examiner has some idea as to the type of poison for which he is looking.”
    12
    Some of the photocopies in the journal were made from a library book at
    Central Piedmont Community College in Charlotte, North Carolina. Trepal
    attended Central Piedmont Community College from 1974–1975.
    3.     Trepal’s Chemistry and Criminal Background
    Several witnesses testified about Trepal’s chemistry experience, which went
    back well over a decade, and the collection of chemistry equipment Trepal kept in
    his Alturas garage and Sebring home.
    First, DEA Agent Richard Broughton testified that, in the mid-1970s, Trepal
    “was the chemist and mastermind” of a group that produced methamphetamine.
    David Warren, Trepal’s partner in the methamphetamine production scheme, also
    testified to Trepal’s role as chemist for the group.
    Trepal’s methamphetamine production experience was particularly relevant
    because, as Agent Broughton testified, thallium nitrate can be used in the process.
    Specifically, thallium III nitrate can be used to produce phenyl-II-propanone,
    called “P2P,” which “is an immediate precursor used in the manufacture of both
    methamphetamine and amphetamine.” When the P2P is produced, a sediment
    drops out of solution, and that sediment is thallium I nitrate. The P2P “is then
    13
    used to manufacture amphetamine, and the Thallium I Nitrate is disposed of.”10
    Second, a witness confirmed that Trepal kept chemicals and other chemistry
    equipment in the garage of his Alturas home. Calvin Adams, a builder who did
    some work for Trepal and his wife as they were moving into their Alturas home in
    1982 and who helped them with the move, noticed that one of the items he helped
    move into Trepal’s garage “was a plastic milk carton filled with chemical bottles.”
    There were at least four or five boxes of chemicals and chemical bottles and other
    chemistry items. Some of the chemicals were in brown bottles like the bottle
    police found in Trepal’s garage.
    Adams asked Trepal what he was doing with the chemistry items, and
    Trepal replied, “I’m a chemist. I intend to set up a laboratory in the garage.”
    Trepal also had an antique-type bottle capper, which is used to affix metal caps
    onto glass bottles. Trepal told Adams he sometimes made wine for himself and
    capped the wine bottles.
    Third, Trepal’s chemistry collection at the time of his arrest included many
    exotic and dangerous chemicals. Scott Ryland, an analytical chemist for the
    Florida Department of Law Enforcement, analyzed various chemicals that were
    10
    Although there was no evidence Trepal himself used or obtained thallium nitrate during
    his methamphetamine-production days (Warren supplied Trepal with his P2P), as chemist for the
    group Trepal may well have been aware of thallium nitrate’s role in making P2P.
    14
    seized from Trepal’s homes in Alturas and Sebring. These chemicals included
    sodium cyanide, barium chloride, cobalt nitrate, potassium ferricyanide, chromium
    trioxide, platinum oxide, lead chloride, and uranium oxide, all of which are toxic.
    4.    Trepal’s Animosity Toward the Carrs
    Numerous witnesses recounted Trepal’s years of threats, arguments, and
    animosity toward the Carrs. For example, Alan Adams, who did lawn care for
    Trepal in 1982 and 1983, saw Trepal interact with the children who lived at the
    Carrs’ property. Trepal “always got highly upset and usually yelled obscenities at
    them.” Trepal “made threats” toward the Carr children on “several occasions.”
    One time Trepal said, “I will get them.” Another time, Trepal “got highly upset
    when they rode some motorcycles through his yard and said, ‘I’m going to kill
    you.’”
    Margaret Smith, who was Pye’s first wife and the mother of Tammy and
    Travis, lived next door to Trepal for four years. Trepal did not like the Carrs’
    dogs. Several times Smith saw Trepal “throwing sticks or stomping his foot at
    them trying to get them out of his yard.”
    John Schaffer bought the Carrs’ home after Peggy’s death and became
    Trepal’s new neighbor. Trepal told Schaffer that Pye had a drinking problem and
    irritated Trepal by coming over to Trepal’s house while drunk and banging on
    15
    Trepal’s door. Trepal told Schaffer that there was a “big social difference”
    between the Trepal and Carr families because the Trepals were reserved and
    childless and kept to themselves, whereas the Carrs were “kind of redneckish and
    . . . the children weren’t disciplined the way they should be.” The Carr children
    bothered Trepal by playing the radio too loudly and being disrespectful.
    Pye estimated he had disagreements with Trepal at least 10 or 12 times.
    One time the Carrs were “working on [Travis’s] truck in the back of the
    workshop” and they and a visitor were listening to “a party tape” that had risque
    jokes and profanity on it. The tape was played pretty loudly, and Trepal came over
    to talk to Pye about it three times. Pye did not turn the tape down.
    In March 1988, Trepal called the zoning board to complain about the Carrs
    converting their garage to an apartment, which Trepal claimed violated the zoning
    ordinance. A county codes inspector issued the Carrs a notice of violation for
    building without a permit, and Pye later got a permit.
    One day in September 1988, Gelena’s former husband Ronald Chester was
    working on his truck and had the radio on. Trepal asked Chester to turn the radio
    down because Trepal was reading a book. Trepal was shaking and “acted like he
    was upset.” Chester turned the radio down, and “like two minutes later” Trepal
    came and again told Chester to turn the radio down, even though the radio was not
    16
    playing loudly.
    Both Trepal’s and the Carrs’ houses had their water supplied by wells. On
    occasion, each home had to share water by hooking up to the other’s well. In early
    October 1988, at which time one of the wells was supplying water to both houses,
    Trepal came over to the Carrs’ home to complain about their radio playing outside.
    Pye told Trepal they would turn the radio off soon. Trepal left, and they did so.
    Later Travis turned the radio back on while washing his car, and Trepal again
    complained. Pye told Trepal that Travis was “just listening to the radio and
    washing the car.” After Pye went into the house, Trepal disconnected the water
    hose to the Carrs’ home.
    A few days before Peggy Carr became ill, Trepal’s wife had “a discussion”
    with Peggy “about some loud music.” The Carr children were playing the music
    outside and “[i]t was extremely loud even inside [Trepal’s] house.” Trepal’s wife
    asked Peggy to have the Carr children turn their music down. Peggy told Trepal’s
    wife that Peggy “didn’t have to.” Trepal’s wife believed Trepal was home with
    her at the time.
    Trepal’s conversations with law enforcement reflected his animosity toward
    the Carr family. Trepal’s comments also showed that his hostility toward the
    Carrs continued even after Peggy was killed and the rest of the Carrs moved away.
    17
    Trepal told Agent Goreck that Pye Carr was “always trying to sell him something”
    and “tried to sell him everything but his wife.” Trepal continued talking and
    “seemed to get agitated.”
    Trepal told FBI Agent Brad Brekke that the Carrs had not been friendly to
    him and his wife, and that Pye tried to take advantage of them by selling them a
    barbecue cooker Pye had made. Trepal reached an oral agreement to buy Pye’s
    workshop behind his house for $10,000, but Pye backed out of the deal.
    Trepal complained about a lot of people coming and going out of the Carrs’
    house, and their having a lot of trucks. Trepal “acted angry and exhibited
    animosity,” which Agent Brekke “felt was unusual since the incidents . . . were
    seven or eight years old.”
    5.      Florida HRS’s Testing of Washings from Empty Coca-Cola Bottles
    Although part of Martz’s testimony about the full Coca-Cola bottles is
    challenged here, other experts confirmed the presence of thallium in the Coca-
    Cola bottles at the Carrs’ home and in the brown bottle in Trepal’s garage. For
    example, Larry Blackwell, a Florida HRS chemist, tested the samples sent from
    the Carrs’ home, including the washings from the empty Coca-Cola bottles.11
    11
    The empty bottles, which contained nothing visible in them, were tested to see if there
    was any thallium residue in the bottle that could not be seen. This was done by adding to the
    bottle “a concentration of distilled water and nitric acid, which would dissolve any metals,”
    18
    Blackwell used two instruments, an inductively coupled plasma atomic emission
    spectrometer (“AES” or “ICP”) and a graphite furnace atomic absorption
    spectrometer (“AAS”).12 The AES and AAS tests indicate only the presence and
    concentration of the metal searched for (in this case, thallium). They chemically
    decompose any other ions or elements in association with the metal, so they
    cannot indicate what compound of thallium was present in the samples. The
    washings from the empty Coca-Cola bottles were positive for thallium, as were
    urine samples from the Carr family members.
    6.      Havekost’s Testing at FBI Lab
    a.      Full Coca-Cola Bottles—Q1, Q2, and Q3
    The three full bottles of Coca-Cola were sent to the FBI Lab and labeled as
    samples Q1, Q2, and Q3. Donald Havekost, an analytical chemist with the
    Elemental Analysis Unit of the FBI Lab, was asked to analyze the contents of the
    full bottles Q1, Q2, and Q3 for the presence of heavy metal poisons, including
    arsenic, lead, and thallium. Havekost tested the samples using AES and found the
    swirling the distilled water/nitric acid mixture around in the bottle for about a minute, and then
    pouring the resulting “washing” into a sample bottle to be tested using AES and/or AAS.
    12
    The AES measures the intensity and wavelength of light emitted by a sample when it is
    heated, while the AAS measures the intensity and wavelength of light absorbed by the sample
    when it is heated. Each test then compares the light intensity and wavelength to that from a
    known standard.
    19
    “predominant element was thallium.” Havekost found none of the other heavy
    metals for which he tested.
    Once Havekost learned that thallium was present, he again performed an
    AES analysis, this time comparing the result with that from known thallium
    standards he prepared in the laboratory to determine the quantity of thallium
    present in the Coca-Cola. For the bottle labeled Q1, Havekost found 403.6
    milligrams of thallium in the total volume of the bottle. For the bottle labeled Q2,
    Havekost found 915.3 milligrams of thallium. For the bottle labeled Q3, Havekost
    found 767.5 milligrams of thallium.
    b.    Empty Coca-Cola Bottles—Q11, Q12, Q13, and Q14
    Havekost’s laboratory unit received from the Florida HRS laboratory the
    washings from the four empty Coca-Cola bottles, which the FBI labeled Q11,
    Q12, Q13, and Q14. The washings from the four empty bottles contained thallium
    in the following amounts: 4.32 milligrams, 3.65 milligrams, 2.08 milligrams, and
    .62 milligrams.
    c.    Trepal Garage Sample—Q206
    Havekost later received the residue from the brown bottle found in Trepal’s
    garage, which the FBI labeled Q206. The sample consisted of 640 milligrams of
    “beige-colored, dirty-white crystalline material or powder.” Havekost tested the
    20
    powder using scanning electron microscopy (“SEM”). Havekost found thallium in
    the compound.
    d.    Havekost Trial Testimony
    At trial, Havekost testified about his testing of the full bottles Q1 through
    Q3, the washings from the empty bottles Q11 through Q14, and the powder
    residue in the brown bottle, Q206, from Trepal’s garage. Havekost testified that
    he found thallium in all of those samples. Trepal has never challenged Havekost’s
    findings, testing methodology, or trial testimony.
    7.     Martz’s Testimony
    Before Martz tested any samples, thallium had already been found in all of
    them. Martz was asked only to determine what salt of thallium was in the samples
    of Coca-Cola from the full Coca-Cola bottles Q1, Q2, and Q3, and from the
    residue found in the brown bottle Q206. Martz did not test, and did not testify
    about, the washings from the empty Coca-Cola bottles Q11 through Q14.
    Martz first tested the Coca-Cola from the full Q1, Q2, and Q3 bottles.
    Martz testified that he performed a diphenylamine (“DP”) test on all three samples
    and “got a blue color,” which he said indicated the solution “contains a nitrate.”
    Martz testified: “Based on that test I concluded that thallium nitrate was added to
    the Coca-Cola.”
    21
    Martz also performed an ion chromatography (“IC”) test to determine
    whether thallium nitrate was present in the Q1, Q2, and Q3 samples. Martz
    testified that he tested all three samples and again concluded that all three samples
    contained nitrate ions. Based on the DP and IC tests, Martz opined that thallium
    nitrate was in the Q1, Q2, and Q3 samples.13
    On cross-examination, Martz admitted he did not “a hundred percent”
    exclude the possibility that the nitrate he found in the Coca-Cola may have come
    from a source other than the thallium salt that was added, but Martz “found
    nothing else in the Coca-Cola to indicate that anything else was present.”
    Later, Martz received Q206, the brown bottle with white powder in it from
    Trepal’s garage, and was asked to identify the white powder. Martz tested the
    powder using infrared and x-ray diffraction (“XRD”) and concluded the brown
    bottle contained thallium I nitrate.14 Martz did not measure quantitatively the
    amount of substance in the bottle, but “based on the tests [he] did, nothing else
    was identified.” The powder weighed .64 grams, which is about “a little more
    than two aspirin tablets” or one “extra strength capsule” of Tylenol.
    13
    There was no way from those tests to determine whether the thallium nitrate was
    thallium I nitrate or thallium III nitrate. And as to Q1, Q2, and Q3, Martz did not testify whether
    it was I or III, but only that it was thallium nitrate.
    14
    Martz testified that thallium I nitrate and thallium III nitrate “have different crystalline
    structures, and the x-ray equipment is able to differentiate those particular two compounds.”
    22
    8.     Testing by Coca-Cola Corporate Laboratory
    Chemists at the Coca-Cola corporate laboratory tested the effect of adding
    various thallium salts to bottled Coca-Cola.
    Coca-Cola chemists first added various thallium compounds to bottles of
    Coca-Cola to see which would dissolve. The chemists successfully dissolved
    thallium malonate, thallium formate, thallium phosphate, and thallium sulfate in
    the Coca-Cola, and re-capped the bottle. When finished, the Coca-Cola in the re-
    capped bottle “looked the same” as it had before.
    Later the Coca-Cola chemists performed this test using thallium I nitrate
    and thallium III nitrate. The thallium I nitrate dissolved and the Coca-Cola looked
    normal. The thallium III nitrate did not dissolve well. It “gave a . . . brownish
    precipitant” and “[t]he Coca-Cola turned sort of a muddy color.” In time, “the
    muddy color settled to the bottom” of the bottle, but “the beverage looked
    substantially different, much lighter in color, and there was a precipitant or sort of
    a muddy-looking substance at the bottom of the bottle.”
    A Coca-Cola representative came to the FBI Lab and tested the three full
    bottles of Coca-Cola (Q1, Q2, and Q3) for carbonization and pressure. The three
    bottles had lower than Coca-Cola’s normal levels of carbonization and pressure.
    This was evidence that the Coca-Cola bottles had been uncapped so that thallium
    23
    could be added to them, and then recapped. Notably too, a witness had seen
    Trepal with a device used to recap bottles.
    E.    Verdict, Penalty Phase, and Sentence
    After deliberating for six hours, the jury found Trepal guilty of one count of
    first-degree murder, six counts of attempted first-degree murder, seven counts of
    poisoning food or water with intent to kill or injure, and one count of tampering
    with a consumer product.
    In the penalty phase, the State called Dr. Richard Hostler, the neurologist
    who treated Peggy Carr, to testify about the pain Peggy Carr experienced from the
    thallium poisoning, including her complaints of an intense burning sensation in
    her feet and the fact she was in pain for several days, until she became comatose.
    The State called no other witnesses.
    The parties entered into two stipulations. First, they stipulated that Trepal
    (1) “was arrested and convicted of the offense of conspiracy to manufacture
    methamphetamine in 1975,” (2) “was incarcerated for this offense for a period of
    two-and-one-half years,” and (3) had “no record of other criminal convictions.”
    Second, the parties stipulated that Trepal “does not have a history of violent
    behavior.”
    The defense called no witnesses and, apart from the stipulations, presented
    24
    no evidence. After deliberating for about one hour, the jury, by a 9 to 3 vote,
    recommended that the court impose the death penalty.
    The state trial court followed the jury’s recommendation and imposed the
    death penalty on the first-degree murder conviction.
    The state trial court sentenced Trepal to concurrent 90-year sentences on the
    remaining convictions.
    F.    Direct Appeal
    Trepal appealed to the Florida Supreme Court. Trepal argued, inter alia,
    that the evidence was insufficient to support his first-degree murder conviction.
    The Florida Supreme Court affirmed Trepal’s convictions and death sentence.
    Trepal v. State, 
    621 So. 2d 1361
    (Fla. 1993) (“Trepal I”). The Supreme Court
    denied Trepal’s certiorari petition. Trepal v. Florida, 
    510 U.S. 1077
    , 
    114 S. Ct. 892
    (1994).
    G.    Initial State Postconviction Proceedings
    On June 16, 1995, Trepal filed a Florida Rule of Criminal Procedure 3.850
    motion to vacate his convictions and death sentence, which he later amended.
    Trepal’s amended 3.850 motion raised 30 claims, including ineffective assistance
    of counsel. On November 6, 1996, after an evidentiary hearing, the 3.850 court
    issued a 40-page order denying relief on all of Trepal’s claims. Trepal appealed.
    25
    H.    1997 OIG Report
    In April 1997, while Trepal’s 3.850 appeal was pending in the Florida
    Supreme Court, the OIG Report issued. Among other things, the OIG Report
    criticized some of Martz’s testimony about Q1, Q2, and Q3 in the Trepal case.
    The OIG’s main criticism was that Martz’s testimony as to Q1 through Q3
    was “stronger than his analytical results would support.” The OIG Report
    admitted “Martz could have properly opined that certain samples were consistent
    with thallium nitrate having been added to them.” However, the OIG Report
    criticized Martz for testifying that “thallium nitrate was added to the Coca-Cola”
    and that, in his opinion, thallium nitrate was in the Q1, Q2, and Q3 samples.
    The OIG Report also pointed out that Martz had run DP tests on Q1, Q2,
    and Q3 but IC tests on only Q1 and Q2. Because Martz did not run an IC test on
    Q3 (contrary to his trial testimony), the OIG Report opined that Martz did not have
    an analytical basis for stating Q3 was even consistent with the addition of nitrate.
    Third, the OIG Report faulted Martz’s trial testimony about the number of
    tests he performed. Martz was asked whether he had performed any tests other
    than the DP test to determine if there was thallium nitrate in the Coca-Cola
    samples, and Martz answered that he had done “one other test,” IC. But in fact
    Martz ran other tests besides DP and IC, which he did not mention at trial. Fourth,
    26
    the OIG Report criticized Martz for not performing certain additional tests such as
    (1) the “validation experiment of adding thallium nitrate to known unadulterated
    Coca-Cola” and running the DP and IC tests on this known sample, and (2)
    quantifying the nitrate he identified in Q1 through Q3 and comparing the amount
    of nitrate to the amount of thallium that Havekost found in those samples.
    Additionally, the OIG Report indicated that Martz’s notes were lacking in detail
    and in some instances inaccurate.
    The OIG Report concluded that Martz’s work on the Trepal case
    demonstrated “a lower threshold of scientific proof than is generally accepted in
    forensic science” and a “lack [of] appropriate scientific rigor in [Martz’s] approach
    to examinations.”
    I.    Remand and Another 3.850 Evidentiary Hearing in Trial Court
    After the OIG Report was issued, and upon Trepal’s motion, the Florida
    Supreme Court stayed Trepal’s appeal and relinquished jurisdiction to the 3.850
    court. Trepal then amended his Rule 3.850 motion to raise, among other things, a
    Giglio claim as to his convictions. The 3.850 court held an evidentiary hearing.
    1.     Roger Martz
    Trepal’s first witness was Martz. Martz discussed his methodology and
    testimony and acknowledged some errors, but ultimately held fast to his opinion at
    27
    trial that thallium nitrate had been added to Q1, Q2, and Q3, the full Coca-Cola
    bottles.
    Martz believed the OIG Report contained three major criticisms of his work
    in the Trepal case: (1) Martz gave a stronger opinion than the OIG believed was
    warranted when he opined the thallium nitrate “was added” to the samples instead
    of the results being “consistent with thallium nitrate having been added”; (2)
    Martz’s notes were incomplete and in places inaccurate; and (3) Martz said all
    three samples Q1 through Q3 were tested for nitrate, but Q3 was not tested using
    the IC.
    Martz acknowledged he could have done a better job of taking notes, and he
    erred in not mentioning that he did not run the IC test on Q3. But neither failure
    affected his final report or final opinion. Martz’s opinion was still that thallium
    nitrate was added to the Coca-Cola. Martz testified that “in hindsight, [he]
    probably should have” tested all three samples using the IC test, but “a lot of time
    if we have multiple samples, we wouldn’t test all of them. We would test a
    representative sample for the confirmatory test just to speed things up.”
    As to Q3, Martz did no other tests besides the DP test. Martz justified his
    conclusion that Q3 had nitrate in it, despite only running one test on that sample:
    I have 25 years of experience testing samples that are associated with
    28
    the case and doing representative samples from those cases, that if you
    take two out of three of the samples, they both have thallium in it, two
    of the three have nitrate, and the third one has a presumptive test for
    nitrate, I used my 25 years—or 20 years of experience working these
    type of cases to conclude that the third sample, even though I didn’t do
    the confirmative test, the only logical explanation would be nitrate.
    Martz also explained that the DP test is a presumptive screening test for
    oxidizing agents, such as nitrates. The DP test was positive for Q1, Q2, and Q3,
    and negative for an unadulterated Coca-Cola sample. A positive result is indicated
    by a blue color.
    At Trepal’s trial, Martz testified that when you pour DP into a solution that
    contains a nitrate, “you get a blue color.” However, that testimony failed to
    acknowledge that “there’s other chemicals that will give a blue color” in a DP test.
    Although Martz had first testified at trial that his conclusion that thallium nitrate
    was added to the Coca-Cola was based on the DP test, later in his trial testimony
    he clarified that he had also relied on the IC test results in reaching that
    conclusion.15
    Martz testified that the IC is used as a “confirmatory test” to confirm the
    15
    Martz conducted four other tests on the Coca-Cola bottle samples: mass spectrometry
    (“MS”), x-ray diffraction (“XRD”), scanning electron microscopy (“SEM”), and liquid
    chromatography (“LC”). Martz’s MS testing of the samples “wasn’t successful,” and he did not
    rely on it for any of his conclusions. Martz tested the Q1 sample, but not Q2 or Q3, using XRD
    and SEM. The tests other than DP “were to give [Martz] negative results, and [he] didn’t need to
    repeat them on the other samples.” In short, Martz did not mention the testing other than DP and
    IC because his “opinion was basically . . . from the [DP] test and the [IC].”
    29
    results of the DP test. However, without a positive result on both tests, Martz
    “would not call it a positive nitrate.”
    Martz acknowledged that neither the DP nor the IC tests alone provide
    positive identification for nitrate (by themselves, each test can at best produce
    results “consistent with” nitrate). But Martz stated that if both tests are positive,
    then in his opinion you have proven the presence of nitrate. And, both the DP and
    IC tests were positive for the Coca-Cola in Q1 and Q2. Martz stated that
    “generally in forensic science, you do a multiple of tests, at least two, in order to
    prove something is present because of the fact that you can get false positives.”
    In the State’s cross-examination, Martz pointed out that the OIG never said
    Martz’s actual testing of the samples in the Trepal case was done improperly. The
    OIG merely questioned the documentation and testimony.
    Martz also opined that “based on the data [he] provided,” he did not believe
    anyone could say thallium nitrate was not added to the Coca-Cola samples. That
    is because thallium is present and there are elevated levels of nitrate.16
    16
    At the 3.850 hearing, two other FBI toxicology experts testified: (1) Thomas Jourdan,
    who worked in the FBI Lab’s Chemistry and Toxicology Unit from 1992 to 1997 and served as
    chief of the Materials and Devices Unit since 1997; and (2) Steven Burmeister, the chief of the
    FBI Lab’s Chemistry and Toxicology Unit. Both agreed that to a reasonable scientific certainty,
    thallium nitrate was added to Q1 and Q2, and they gave reasons for their opinions. Both could
    not testify as to Q3 because no IC test was run on Q3. In its ruling, the 3.850 court discounted
    the testimony of Jourdan and Burmeister, so we do not rely on it.
    30
    2.     Marland Dulaney, Jr.
    Trepal’s main witness in the state collateral proceeding was Marland
    Dulaney, Jr., a consulting toxicologist. Dulaney opined that he could not rely on
    the IC charts to a “reasonable scientific certainty” because Martz did not run
    proper standards and blanks. Martz did not run chloride or sulfate standards to
    confirm where chloride and sulfate ions appeared on the charts. Martz ran a
    nitrate standard, but did so by adding known nitrate to water, not to Coca-Cola.
    Dulaney did not dispute that thallium was present in the Coca-Cola samples.
    But Dulaney opined that all one can say with reasonable scientific certainty about
    Q1, Q2, and Q3 is that they contain thallium. Dulaney could not rule out the
    possibility that thallium nitrate was added to the Coca-Cola samples. Moreover,
    Dulaney could not testify that the thallium salt present in the Q samples was
    something other than thallium I nitrate, because he had insufficient information.
    Dulaney testified that Martz’s “approach is so bad, . . . it has so many holes that
    anybody can say anything that they want, because they have to make assumptions,
    and if you assume this and this and this, then this is true.” But the data provided
    no way to test the assumptions.
    Based on his review of the data, Dulaney opined that the conclusion that
    thallium nitrate was added to Q1 and Q2 cannot be made to a reasonable degree of
    31
    scientific certainty. According to Dulaney, adding nitrate to Coca-Cola and
    running an IC on it was “the fundamental step that would allow us to say that
    thallium nitrate was added to Coca-Cola,” and that was not done.
    3.     Frederic Whitehurst
    Frederic Whitehurst, the former FBI Lab examiner whose complaints began
    the OIG investigation, worked in the FBI Lab from 1986 to 1998. Whitehurst’s
    area of expertise was explosives, but he was familiar with the tests and equipment
    used in the Trepal case.
    Whitehurst opined that the IC testing in the Trepal case did not meet
    acceptable scientific standards. Whitehurst agreed with Dulaney that Martz
    should have run a standard in Coca-Cola instead of water “to see what effect the
    Coke and the instrument has on the chromatography.”
    Nonetheless, Whitehurst had no doubt that thallium was found in the Coca-
    Cola. But Whitehurst believed there were “too many unknowns” to conclude
    which form of thallium was added. However, Whitehurst admitted that, based on
    the test results he reviewed, Q1 and Q2 are consistent with thallium nitrate having
    been added to them, and neither he nor anyone else could, based on the data
    available, rule out thallium nitrate having been added to the samples. In
    32
    Whitehurst’s opinion, there was not enough data to say one way or another.17
    J.     Denial of Trepal’s Amended Rule 3.850 Motion
    On October 26, 2000, the 3.850 court issued a 36-page order denying
    Trepal’s amended Rule 3.850 motion. The 3.850 court found that “[n]o real attack
    [was] made on the findings of Q206,” the brown bottle from Trepal’s garage.
    Thus, the court limited its discussion on the testing of Q206 to the relationship of
    Q206 to Q1, Q2, and Q3, the samples from the full Coca-Cola bottles.
    As to Q1, Q2, and Q3, the 3.850 court found the following instances of false
    testimony by Martz at Trepal’s trial: (1) Martz stated a positive DP test indicates
    the presence of a nitrate (instead of saying the presence of an oxidizing ion, of
    which nitrate is an example); (2) Martz stated nitrate was not present in the
    unadulterated Coca-Cola (whereas the IC results indicated a nitrate could be
    present, although the DP test was negative); (3) Martz stated he ran IC tests on Q1,
    Q2, and Q3 (when he only tested Q1 and Q2); (4) Martz did not reveal he
    performed additional testing on the Q samples (beyond the DP and IC tests he
    17
    Trepal’s trial attorneys Jonathan Stidham and Dabney Conner testified at the 3.850
    evidentiary hearing. Stidham and Conner testified that the comparison of the contents of the
    Q206 bottle to the Q1 through Q3 Coca-Cola bottles was important to the case, and thus defense
    counsel hired their own chemistry expert to try to disprove that the thallium in the Coca-Cola
    bottles came from Q206. However, the defense expert was not able to do so, and so they did not
    call him to testify. The defense expert’s analysis did not replicate Martz’s work and proceeded
    along completely different lines.
    33
    discussed at trial); and (5) Martz stated that the tests indicated thallium nitrate was
    added to Q1, Q2, and Q3 (instead of that the test results were consistent with
    thallium nitrate having been added to Q1 and Q2, and consistent with an oxidizing
    ion being present in Q3).
    The 3.850 court called Martz’s trial conduct “outrageous and shocking,” but
    noted that regardless, to prevail on any of his claims, Trepal must show he was
    prejudiced. Thus, “the court must look to the effect the evidence would have on
    the jury verdict, both in the guilt phase and the penalty phase.”
    As to Trepal’s Giglio claim, the 3.850 court discussed the materiality
    standard, as follows:
    [Trepal] claims a violation of Giglio for use of false testimony at trial.
    Giglio v. United States, 
    405 U.S. 150
    (1972). . . . Giglio holds that a
    conviction based on false or perjured testimony, which the prosecution
    knew or should have known was false, violates due process when such
    information is material. The materiality prong is the same as that used
    in Brady. See Rose v. State, WL 1508576 (Fla. 2000). False
    information is material if “there is a reasonable likelihood that it could
    have [a]ffected the jury verdict.” 
    Id. The 3.850
    court determined that the materiality question “implies a comparison”
    between Martz’s “actual testimony” at trial and “what Martz could have truthfully
    testified to at trial.”
    Denying relief, the 3.850 court concluded that Trepal could not show
    34
    prejudice. The 3.850 court found that “given the test results that Martz could have
    rightfully testified about and considering all the other evidence in the case,” there
    was “no reasonable likelihood that the verdict would have been different.”18
    K.    Rule 3.850 Appeal
    Trepal appealed the denial of his Rule 3.850 motion to the Florida Supreme
    Court, which affirmed. Trepal v. State, 
    846 So. 2d 405
    (Fla. 2003) (“Trepal II”),
    receded from in part by Guzman v. State, 
    868 So. 2d 498
    , 506 (Fla. 2003).
    As to Trepal’s Giglio claim, the Florida Supreme Court quoted at length the
    3.850 court’s order. Trepal 
    II, 846 So. 2d at 410-26
    . In particular, the Florida
    Supreme Court quoted the 3.850 court’s statements that: (1) the Giglio
    “materiality prong is the same as that used in Brady”; (2) “[f]alse information is
    material if ‘there is a reasonable likelihood that it could have affected the jury
    verdict’”; (3) in conducting the Giglio analysis, Martz’s “actual testimony should
    be compared to what Martz could have truthfully testified to at trial”; (4) in the
    18
    In full, the 3.850 court said:
    As to the guilt phase, the court finds . . . that there is no reasonable likelihood
    that the verdict would have been different. This case was based almost entirely on
    circumstantial evidence. The testing results of the Coke samples and Q206 were the
    only direct evidence of Trepal’s guilt. Even so, given the test results that Martz could
    have rightfully testified about and considering all the other evidence in the case, the
    court finds no reasonable likelihood that the guilt phase results would have been
    different. Although this is a circumstantial evidence case, the evidence was strong.
    Turning to the penalty phase, . . . . [t]he court finds that there is no reasonable
    likelihood that the verdict would have been different. . . .
    35
    guilt phase, “there is no reasonable likelihood that the verdict would have been
    different”; and (5) in the penalty phase, “there is no reasonable likelihood that the
    verdict would have been different.” Trepal 
    II, 846 So. 2d at 425-26
    (emphasis
    added and omitted).
    The Florida Supreme Court then set forth its own analysis.19 
    Id. at 426-28.
    The Florida Supreme Court agreed with the 3.850 court’s conclusion “that Trepal
    was not impermissibly prejudiced by the testimony of Martz.” 
    Id. at 426.
    To explain why, the Florida Supreme Court reviewed the 3.850 court’s
    findings on specific false or misleading statements Martz made at Trepal’s trial:
    In the present case, the circuit court found that the following statements
    made at trial by Martz were improper for the following reasons:
    - Martz stated: “And when you pour that [i.e., diphenylamine or
    DP] into a solution which contains a nitrate you get a blue color.” (The
    circuit court, however, found as follows: when you pour DP into a
    solution that contains an oxidizing ion—which may or may not be a
    nitrate—you get a blue color.)
    - Martz stated: “Based on that test [i.e., the DP test] I concluded
    that thallium nitrate was added to the Coca-Cola.” (The circuit court,
    however, found as follows: all that could be concluded based on the DP
    test—in conjunction with the other tests—was that the test results were
    consistent with the presence of thallium nitrate.)
    - Martz stated: “No nitrates were present in the unadulterated
    Coca-Cola.” (The circuit court, however, found as follows: ion
    19
    The Florida Supreme Court noted that the Martz testimony claim involved a mixed
    question of law and fact. Trepal 
    II, 846 So. 2d at 426
    . Thus, the Florida Supreme Court
    reviewed the 3.850 court’s “ultimate ruling” de novo but its factual findings based on whether
    they were “supported by competent substantial evidence.” 
    Id. at 427.
    36
    chromatography or IC testing showed the presence of a substance that
    could have been a nitrate in the unadulterated Coke.)
    - “In this particular case, when I tested the Coca-Cola [via IC] the
    results were positive for the nitrate ion.” (The circuit court, however,
    found as follows: the IC test can show only the presence of an oxidizing
    ion—which may or may not be a nitrate.)
    - Martz was asked: “Did you test each of the samples on the ion
    chromatograph to determine whether nitrate was present?” He
    responded: “Yes, I did.” (The circuit court, however, found as follows:
    Martz did not test each sample. He did not test the third sample, i.e., Q3,
    on the ion chromatograph.)
    - Martz stated: “On three samples that I tested, all three contained
    nitrate ions.” (The circuit court, however, found as follows: on two
    samples that Martz tested, all that he appropriately could have attested
    to was that the tests were consistent with the presence of a nitrate; and
    that on the third sample, the tests were consistent with the presence of
    an oxidizing ion—which may or may not have been a nitrate.)
    - Martz was asked: “Based on those two tests [i.e., DP and IC], is
    it your opinion that what was in those three Coca-Colas, sir, was
    thallium nitrate?” He responded: “That is correct.” (The circuit court,
    however, found—as noted above—that all that Martz appropriately
    could have attested to was that the tests were consistent with the
    presence of thallium nitrate.)
    
    Id. at 427
    (brackets in original). The Florida Supreme Court then noted
    unchallenged, incriminating facts that existed regardless of Martz’s false
    testimony:
    Regardless of the above improprieties in the testimony of Martz (and
    regardless of the improprieties in his testing practices and omissions in
    his testimony), the following conclusions nevertheless can properly be
    drawn from the present record:
    [1.] Peggy Carr died from ingesting thallium (of an undetermined
    type).
    [2.] Of the various forms of thallium, only thallium sulfate and
    37
    thallium nitrate (sub-group I) dissolve in Coca-Cola without changing
    the appearance of the Coke or foaming out of the bottle.
    [3.] The brown bottle found in Trepal’s garage contained (a)
    thallium, and (b) an oxidizing ion consistent with the presence of a
    nitrate.
    [4.] Five empty Coca-Cola bottles found in the Carr household
    contained thallium (of an undetermined type).
    [5.] Tests on two unopened bottles of Coca-Cola found in the Carr
    household (a) showed the presence of thallium, and (b) yielded results
    that were consistent with the presence of a nitrate.
    [6.] Tests on a third unopened bottle of Coca-Cola found in the
    Carr household (a) showed the presence of thallium, and (b) yielded
    results that were consistent with the presence of an oxidizing ion (which
    may or may not have been a nitrate).
    
    Id. at 427
    -28.
    The Florida Supreme Court concluded that the 3.850 court’s “factual
    findings are supported by competent, substantial evidence in the record, and the
    court properly concluded—based on those findings—that the prejudice suffered by
    Trepal was insufficient to warrant a new trial. We find no error.” 
    Id. at 428.
    The Florida Supreme Court’s majority opinion did not state explicitly what
    materiality standard it was applying, and did not comment upon (whether to
    approve or disapprove) the materiality standard applied by the 3.850 court.
    In a special concurrence, two Florida Supreme Court justices clarified the
    different prejudice standards relating to Brady and Giglio claims. Trepal 
    II, 846 So. 2d at 437
    (Pariente, J., concurring). The concurrence explained its view that
    38
    the 3.850 court incorrectly stated that the Brady and Giglio materiality standards
    were identical. 
    Id. at 438-39.
    Nevertheless, the justices concurred because, even
    if Martz’s false testimony satisfied the other elements of the Giglio test, the
    testimony “could not have led the jury to find other than that Trepal intentionally
    poisoned his neighbors with thallium, resulting in the death of Peggy Carr.” 
    Id. at 439.
    Several months after Trepal II, the Florida Supreme Court, in a unanimous
    decision, noted its precedent lacked clarity and explained that the Brady and
    Giglio materiality standards are different. Guzman v. State, 
    868 So. 2d 498
    , 505-
    06 (Fla. 2003). Under Brady, one must show “a reasonable probability that the
    undisclosed evidence would have produced a different verdict,” whereas under
    Giglio, one must show that “there is any reasonable likelihood that the false
    testimony could have affected the judgment of the jury.” 
    Guzman, 868 So. 2d at 506
    (emphasis added).
    After Guzman, Trepal moved the Florida Supreme Court to reopen his
    appeal. Trepal argued that he was entitled to a new trial or, at least, a remand to
    the 3.850 court for a proper Giglio analysis.
    On December 6, 2004, in an unpublished decision, the Florida Supreme
    Court summarily denied relief “on the merits.”
    39
    L.     Federal Habeas Proceedings
    On August 17, 2005, Trepal filed in the district court his 28 U.S.C. § 2254
    petition for a writ of habeas corpus. Trepal’s § 2254 petition claimed, inter alia,
    that Martz’s false testimony violated Giglio.
    On June 15, 2010, the district court issued a 75-page order denying Trepal’s
    § 2254 petition. The district court concluded Trepal did not show that the Florida
    Supreme Court’s Trepal II decision was contrary to or based on an unreasonable
    application of Giglio.
    The district court granted Trepal a COA on “[w]hether the decision in
    Trepal 
    II, 846 So. 2d at 428
    —that ‘the prejudice suffered by Trepal as a result of
    Martz’s improprieties was insufficient to warrant a new trial’—is objectively
    unreasonable.”20 Trepal appealed to this Court.
    II. STANDARD OF REVIEW
    The Antiterrorism and Effective Death Penalty Act of 1996 (“AEDPA”),
    Pub. L. No. 104-132, 110 Stat. 1214, “imposes a highly deferential standard for
    20
    The district court also granted Trepal a COA as to “[w]hether the decision in Trepal 
    II, 846 So. 2d at 428
    —‘that the [3.850] court’s factual findings are supported by competent,
    substantial evidence in the record’—is objectively unreasonable.” In his initial brief on appeal,
    however, Trepal does not argue that the state 3.850 court’s findings were not supported by the
    record. In any event, the record amply supports all the state 3.850 court’s fact findings and we
    conclude the Florida Supreme Court’s decision was not unreasonable. See 28 U.S.C.
    § 2254(d)(2).
    40
    evaluating state-court rulings and demands that state-court decisions be given the
    benefit of the doubt.” Hardy v. Cross, 565 U.S. —, 
    132 S. Ct. 490
    , 491 (2011)
    (quoting Felkner v. Jackson, 562 U.S. —, 
    131 S. Ct. 1305
    , 1307 (2011)). Section
    2254, as amended by AEDPA, provides that a federal court shall not grant federal
    habeas relief to a state prisoner on a claim adjudicated on the merits in state court
    unless the state court’s adjudication of the claim: (1) “resulted in a decision that
    was contrary to, or involved an unreasonable application of, clearly established
    Federal law, as determined by the Supreme Court of the United States”; or (2)
    “resulted in a decision that was based on an unreasonable determination of the
    facts in light of the evidence presented in the State court proceeding.” 28 U.S.C.
    § 2254(d).
    “We review de novo the district court’s decision about whether the state
    court acted contrary to clearly established federal law, unreasonably applied
    federal law, or made an unreasonable determination of fact.” Johnson v. Upton,
    
    615 F.3d 1318
    , 1330 (11th Cir. 2010) (quotation marks omitted), cert. denied, 
    131 S. Ct. 3041
    (2011).
    III. DISCUSSION
    In order to discuss the issue of whether the Florida courts contravened or
    unreasonably applied controlling federal law here, we first set forth the governing
    41
    Giglio materiality standard.
    A.     Giglio Standard
    In Giglio v. United States, 
    405 U.S. 150
    , 
    92 S. Ct. 763
    (1972), the Supreme
    Court held that when the prosecution solicits or fails to correct known false
    evidence, due process requires a new trial where “the false testimony could in any
    reasonable likelihood have affected the judgment of the 
    jury.” 405 U.S. at 154
    , 92
    S. Ct. at 766 (ellipsis omitted). Giglio error, which “is a species of Brady error,”
    exists “when ‘the undisclosed evidence demonstrates that the prosecution’s case
    included perjured testimony and that the prosecution knew, or should have known,
    of the perjury.’” Ventura v. Att’y Gen., 
    419 F.3d 1269
    , 1276-77 (11th Cir. 2005)
    (quoting United States v. Agurs, 
    427 U.S. 97
    , 103, 
    96 S. Ct. 2392
    , 2397 (1976)).
    “To establish a Giglio claim, a habeas petitioner must prove: (1) the
    prosecutor knowingly used perjured testimony or failed to correct what he
    subsequently learned was false testimony; and (2) such use was material, i.e., that
    there is any reasonable likelihood that the false testimony could have affected the
    judgment.” Guzman v. Sec’y, Dep’t of Corr., 
    663 F.3d 1336
    , 1348 (11th Cir.
    2011) (“Guzman II”) (quotation marks and ellipsis omitted).21
    21
    We refer to our December 7, 2011 Guzman decision as “Guzman II” to distinguish it
    from the Florida Supreme Court’s 2003 decision in Guzman v. State, 
    868 So. 2d 498
    , 505-06
    (Fla. 2003), discussed earlier, which we refer to as “Guzman.”
    42
    The Giglio materiality standard is “different and more defense-friendly”
    than the Brady materiality standard, as we have explained:
    Where there has been a suppression of favorable evidence in violation
    of Brady v. Maryland, 
    373 U.S. 83
    , 
    83 S. Ct. 1194
    , 
    10 L. Ed. 2d 215
          (1963), the nondisclosed evidence is material: “if there is a reasonable
    probability that, had the evidence been disclosed to the defense, the
    result of the proceeding would have been different. A ‘reasonable
    probability’ is a probability sufficient to undermine confidence in the
    outcome.” United States v. Bagley, 
    473 U.S. 667
    , 682, 
    105 S. Ct. 3375
    ,
    3383, 
    87 L. Ed. 2d 481
    (1985). A different and more defense-friendly
    standard of materiality applies where the prosecutor knowingly used
    perjured testimony, or failed to correct what he subsequently learned
    was false testimony. Where either of those events has happened, the
    falsehood is deemed to be material “if there is any reasonable likelihood
    that the false testimony could have affected the judgment of the jury.”
    United States v. Agurs, 
    427 U.S. 97
    , 103, 
    96 S. Ct. 2392
    , 2397, 
    49 L. Ed. 2d 342
    (1976) (emphasis added); accord Giglio v. United States,
    
    405 U.S. 150
    , 154, 
    92 S. Ct. 763
    , 766, 
    31 L. Ed. 2d 104
    (1972); Napue v.
    Illinois, 
    360 U.S. 264
    , 271, 
    79 S. Ct. 1173
    , 1178, 
    3 L. Ed. 2d 1217
    (1959).
    United States v. Alzate, 
    47 F.3d 1103
    , 1109-10 (11th Cir. 1995). Thus, for Brady
    violations, the defendant must show a reasonable probability the result would have
    been different, but for Giglio violations, the defendant has the lighter burden of
    showing that there is any reasonable likelihood that the false testimony could have
    affected the jury’s judgment. 
    Alzate, 47 F.3d at 1109-10
    . The Brady materiality
    standard “is substantially more difficult for a defendant to meet than the ‘could
    43
    have affected’ standard” under Giglio.22 
    Id. at 1110
    n.7.
    B.     Whether Trepal has Satisfied § 2254(d)
    A threshold issue is the proper standard of deference that applies to the
    Florida Supreme Court’s denial of Trepal’s Giglio claim—that is, whether Trepal
    has shown that the Florida Supreme Court’s denial of his claim in Trepal II was
    contrary to or based on an unreasonable application of clearly established Supreme
    Court precedent. See 28 U.S.C. § 2254(d)(1). Here, the relevant Supreme Court
    precedent is Giglio, for “no Supreme Court case since Giglio itself has squarely
    addressed a Giglio claim.” 
    Ventura, 419 F.3d at 1279
    .
    Trepal argues that we should review the merits of his claim de novo because
    the Florida Supreme Court’s Trepal II decision was contrary to Giglio in that it
    applied the wrong materiality standard. Trepal is correct that a state court decision
    falls under the “contrary to” prong of § 2254(d)(1) if it “applies a rule that
    contradicts the governing law set forth” in a prior Supreme Court holding. Price
    v. Vincent, 
    538 U.S. 634
    , 640, 
    123 S. Ct. 1848
    , 1853 (2003) (quotation marks
    omitted). However, it is less than clear whether the Florida Supreme Court in
    22
    “[T]he reason the lower materiality burden applies where there is knowing use of
    perjured testimony is that such a situation involves prosecutorial misconduct and a corruption of
    the truth-seeking function of the trial.” 
    Alzate, 47 F.3d at 1110
    ; accord 
    Agurs, 427 U.S. at 103
    -
    
    04, 96 S. Ct. at 2397
    .
    44
    Trepal II applied a materiality rule that contradicts Giglio’s.
    The Florida Supreme Court, for its part, did not expressly state what
    materiality standard it applied. Instead, the Florida Supreme Court quoted nearly
    the entire analysis of the 3.850 court, and then stated that it agreed Trepal was not
    prejudiced by Martz’s testimony:
    After evaluating the conflicting testimony of the witnesses, the [3.850]
    court concluded that Trepal was not impermissibly prejudiced by the
    testimony of Martz. We agree.
    ...
    . . . [W]e agree that the prejudice suffered by Trepal as a result of
    Martz’s improprieties was insufficient to warrant a new trial. . . . [W]e
    conclude that the [3.850] court’s factual findings are supported by
    competent, substantial evidence in the record, and the [3.850] court
    properly concluded—based on those findings—that the prejudice
    suffered by Trepal was insufficient to warrant a new trial. We find no
    error.
    Trepal 
    II, 846 So. 2d at 426
    -28 (footnote omitted).
    As to the quoted portions of the 3.850 court’s analysis, even those are not
    entirely clear as to whether the 3.850 court mis-applied Giglio’s materiality
    standard. Although the 3.850 court stated—incorrectly—that the “materiality
    prong [of Giglio] is the same as that used in Brady,” its very next sentence
    correctly sets forth the Giglio standard: “False information is material if ‘there is a
    reasonable likelihood that it could have affected the jury verdict.’” Trepal 
    II, 846 So. 2d at 425
    .
    45
    We need not resolve the question of the proper standard of deference to the
    Florida Supreme Court’s adjudication of Trepal’s claim of Giglio error.23 Instead,
    we adopt an approach the United States Supreme Court itself has employed when
    a petitioner fails to show prejudice even under de novo review:
    Even if the state court used an incorrect legal standard, we need not
    determine whether AEDPA’s deferential standard of review, 28 U.S.C.
    § 2254(d), applies in this situation. Cf. Williams v. Taylor, 
    529 U.S. 362
    , 397–398, 
    120 S. Ct. 1495
    , 
    146 L. Ed. 2d 389
    (2000). That is because,
    even if AEDPA deference does not apply, Thompkins cannot show
    prejudice under de novo review, the more favorable standard of review
    for Thompkins. Courts cannot grant writs of habeas corpus under § 2254
    by engaging only in de novo review when it is unclear whether AEDPA
    deference applies, § 2254(d). In those situations, courts must resolve
    whether AEDPA deference applies, because if it does, a habeas
    petitioner may not be entitled to a writ of habeas corpus under
    § 2254(d). Courts can, however, deny writs of habeas corpus under
    § 2254 by engaging in de novo review when it is unclear whether
    AEDPA deference applies, because a habeas petitioner will not be
    entitled to a writ of habeas corpus if his or her claim is rejected on de
    novo review, see § 2254(a).
    Berghuis v. Thompkins, 560 U.S. —, 
    130 S. Ct. 2250
    , 2265 (2010) (emphasis
    added). As was the case for the Supreme Court in Thompkins, we need not
    determine whether the state supreme court used an incorrect legal standard, for we
    23
    We are aware that the Supreme Court has instructed us that, on federal habeas review,
    we are to give state court decisions “the benefit of the doubt.” Cullen v. Pinholster, 563 U.S. —,
    
    131 S. Ct. 1388
    , 1398 (2011) (quoting Woodford v. Visciotti, 
    537 U.S. 19
    , 24, 
    123 S. Ct. 357
    ,
    360 (2002)). Our concurring colleague points out good reasons why we should conclude the
    Florida Supreme Court did not apply an incorrect standard in its adjudication of Trepal’s Giglio
    claim. But Trepal’s claim fails even under de novo review.
    46
    conclude that Trepal cannot prevail even under de novo review.
    To prevail here, Trepal must show that a Giglio error resulted in “actual
    prejudice” to him under the standard set forth in Brecht v. Abrahamson, 
    507 U.S. 619
    , 
    113 S. Ct. 1710
    (1993). See Guzman 
    II, 663 F.3d at 1347
    ; see also Mansfield
    v. Sec’y, Dep’t of Corr., — F.3d —, No. 09-12312, slip op. at 12 (11th Cir. May 9,
    2012) (“On collateral review, a federal constitutional error is harmless unless there
    is ‘actual prejudice,’ meaning that the error had a ‘substantial and injurious effect
    or influence’ on the jury’s verdict.” (quoting 
    Brecht, 507 U.S. at 637
    , 113 S. Ct. at
    1722)). Even if Trepal shows part of Martz’s testimony was false about some
    things, and even assuming arguendo that Martz’s false testimony (1) can be
    imputed to the state prosecutor,24 and (2) was material under Giglio, Trepal has not
    shown that he suffered the actual prejudice required under Brecht. We explain
    below.
    24
    There is a substantial issue as to whether FBI Agent Martz’s knowing false testimony
    can be imputed to the Florida State Attorney who prosecuted the Trepal case. See, e.g., Moon v.
    Head, 
    285 F.3d 1301
    , 1309-10 (11th Cir. 2002) (noting that (1) a prosecutor has a duty to learn
    of any favorable evidence known to others acting on the government’s behalf, including law
    enforcement officers, and (2) thus knowledge possessed by any member of the “prosecution
    team” is imputed to the prosecutor, but (3) whether knowledge held by members of one
    governmental entity can be imputed to a prosecutor working for a different governmental entity
    is determined using “a case-by-case analysis of the extent of interaction and cooperation between
    the two governments” (quoting United States v. Antone, 
    603 F.2d 566
    , 570 (5th Cir. 1979)).
    The State contends that Martz was not a part of the “prosecution team,” that he was
    simply serving as an expert witness called to testify about his testing of the evidence, and that his
    overstatement of his opinions was neither known nor countenanced by anyone in the State
    Attorney’s office. We need not reach this issue to decide this case.
    47
    C.     Brecht “Actual Prejudice” Standard for Federal Habeas Relief
    In Brecht, the Supreme Court began by discussing its prior decision in
    Chapman v. California, 
    386 U.S. 18
    , 
    87 S. Ct. 824
    (1967). See 
    Brecht, 507 U.S. at 622
    , 
    630, 113 S. Ct. at 1713
    , 1717. The Brecht Court pointed out that Chapman
    “rejected the argument that the Constitution requires a blanket rule of automatic
    reversal in the case of constitutional error, and concluded instead that ‘there may
    be some constitutional errors which in the setting of a particular case are so
    unimportant and insignificant that they may, consistent with the Federal
    Constitution, be deemed harmless.’” 
    Brecht, 507 U.S. at 630
    , 113 S. Ct. at 1717
    (quoting 
    Chapman, 386 U.S. at 22
    , 87 S. Ct. at 827). Accordingly, constitutional
    defects in criminal trials fall into two classes: (1) “structural defects,” which
    require automatic reversal of a conviction, and (2) “trial errors,” which are subject
    to harmless error analysis.25 See 
    id. at 629–30,
    113 S. Ct. at 1717. The standard
    25
    The Brecht Court explained the distinction between trial error and structural defects:
    Trial error occurs during the presentation of the case to the jury, and is amenable to
    harmless-error analysis because it may be quantitatively assessed in the context of
    other evidence presented in order to determine the effect it had on the trial. At the
    other end of the spectrum of constitutional errors lie structural defects in the
    constitution of the trial mechanism, which defy analysis by harmless-error standards.
    The existence of such defects—deprivation of the right to counsel, for
    example—requires automatic reversal of the conviction because they infect the entire
    trial process.
    
    Brecht, 507 U.S. at 629-30
    , 113 S. Ct. at 1717 (citations, quotation marks, footnotes, brackets,
    and ellipsis omitted).
    48
    Chapman set for harmlessness of constitutional trial error was whether the
    reviewing court was “able to declare a belief that [the error] was harmless beyond
    a reasonable doubt.” Id. at 
    630, 113 S. Ct. at 1717
    (quoting 
    Chapman, 386 U.S. at 24
    , 87 S. Ct. at 828).
    Chapman was a direct-appeal case, and until Brecht, the Supreme Court had
    not had occasion to squarely address whether the Chapman “harmless beyond a
    reasonable doubt” standard applied to cases on collateral review. 
    Brecht, 507 U.S. at 630
    , 113 S. Ct. at 1718. Brecht determined that Chapman’s harmless error
    standard did not apply on collateral review. 
    Id. at 623,
    630–38, 113 S. Ct. at 1714
    ,
    1718–22.
    Instead, the Brecht Court concluded that the appropriate harmless-error
    standard for habeas review of criminal convictions was whether the constitutional
    error “had substantial and injurious effect or influence in determining the jury’s
    verdict.” 
    Id. at 623,
    113 S. Ct. at 1714 (quoting Kotteakos v. United States, 
    328 U.S. 750
    , 776, 
    66 S. Ct. 1239
    , 1253 (1946)). The Supreme Court reasoned that
    “granting habeas relief merely because there is a ‘reasonable possibility’ that trial
    error contributed to the verdict is at odds with the historic meaning of habeas
    corpus—to afford relief to those whom society has ‘grievously wronged’”—and
    also imposes social costs and infringes on the states’ sovereignty and interest in
    49
    finality of judgments. 
    Id. at 637,
    113 S. Ct. at 1721 (quotation marks and citations
    omitted). Moreover, “[s]tate courts are fully qualified to identify constitutional
    error and evaluate its prejudicial effect on the trial process under Chapman, and
    state courts often occupy a superior vantage point from which to evaluate the
    effect of trial error,” and thus “it scarcely seems logical to require federal habeas
    courts to engage in the identical approach to harmless-error review that Chapman
    requires state courts to engage in on direct review.” 
    Id. at 636,
    113 S. Ct. at 1721.
    Consequently, the Brecht Court concluded that the Kotteakos
    standard—which derived from the federal harmless-error statute, 28 U.S.C.
    § 2111—was “better tailored” than the Chapman standard “to the nature and
    purpose of collateral review and [was] more likely to promote the considerations
    underlying [the Supreme Court’s] recent habeas cases.” 
    Brecht, 507 U.S. at 638
    ,
    113 S. Ct. at 1722. Thus, to grant habeas relief based on constitutional trial error,
    the federal habeas court must find not only that the error occurred, but that it
    “resulted in ‘actual prejudice,’” that is, “the error had ‘substantial and injurious
    effect or influence in determining the jury’s verdict.’” 
    Id. at 637
    (quoting
    
    Kotteakos, 328 U.S. at 776
    , 66 S. Ct. at 1253; citing United States v. Lane, 474
    
    50 U.S. 438
    , 449, 
    106 S. Ct. 725
    , 732 (1986)).26 The Brecht standard “is more
    favorable to and less onerous on the state, and thus less favorable to the defendant,
    than the Chapman harmless beyond a reasonable doubt standard.” Mansfield, slip
    op. at 13 (quotation marks omitted).
    Giglio error is trial error, not a structural defect. 
    Ventura, 419 F.3d at 1278
    n.3. Therefore, when considering a Giglio claim on federal habeas review, we can
    grant relief on that claim only if (1) the petitioner establishes that a Giglio error
    occurred, and (2) that error had “substantial and injurious effect or influence in
    determining the jury’s verdict.”27 
    Brecht, 507 U.S. at 637
    , 113 S. Ct. at 1722; see
    26
    We do not phrase the Brecht requirement as a burden of proof, for it is not. In O’Neal v.
    McAninch, 
    513 U.S. 432
    , 435, 
    115 S. Ct. 992
    , 994 (1995), the Supreme Court held that if a
    federal habeas court has “grave doubt” about whether a constitutional error is harmless under the
    Brecht standard, which the Court defined as situations in which “the matter is so evenly balanced
    that [the judge] feels himself in virtual equipoise as to the harmlessness of the error,” then “the
    uncertain judge should treat the error, not as if it were harmless, but as if it affected the verdict
    (i.e., as if it has a ‘substantial and injurious effect or influence in determining the jury’s
    verdict’).” 
    Id. The Supreme
    Court further explained:
    [W]e deliberately phrase the issue in this case in terms of a judge’s grave doubt,
    instead of in terms of “burden of proof.” The case before us does not involve a judge
    who shifts a “burden” to help control the presentation of evidence at a trial, but rather
    involves a judge who applies a legal standard (harmlessness) to a record that the
    presentation of evidence is no longer likely to affect. In such a case, we think it
    conceptually clearer for the judge to ask directly, “Do I, the judge, think that the error
    substantially influenced the jury’s decision?” than for the judge to try to put the same
    question in terms of proof burdens (e.g., “Do I believe the party has borne its burden
    of showing . . . ?”).
    
    Id. at 436–37,
    115 S. Ct. at 994–95.
    27
    We emphasize that the Brecht standard is a harmless error test that applies to federal
    habeas review of state convictions. 
    Brecht, 507 U.S. at 634-38
    , 113 S. Ct. at 1720-22; 
    Ventura, 419 F.3d at 1279
    n.4. It does not apply to state courts’ review of their own convictions. Instead,
    51
    Guzman II, 
    663 F.3d 1336
    , 1355 (11th Cir. 2011) (“Having found the state court’s
    decision was an unreasonable application of clearly established federal law, we
    further find that Guzman’s claim is meritorious for all the reasons discussed
    above. But this does not end our inquiry. We must next consider whether
    Guzman’s Giglio claim had a substantial and injurious effect on the outcome of his
    trial.”). Because we consider the Brecht question in the first instance on federal
    habeas review, there is no state court Brecht actual-prejudice finding to review or
    to which we should defer.28 See Mansfield, slip op. at 12 (noting that federal
    habeas courts “apply a different harmless error analysis” than the Chapman
    standard applied by state courts and that “[h]armlessness under the Brecht
    standard is a question of law that we review de novo”). Of course, we still would
    defer to the state court’s other fact findings derived from testimony, documents,
    and what happened at trial and the 3.850 hearing.
    Having determined that the Brecht standard applies, we now consider how it
    compares with, and relates to, Giglio’s materiality standard. We note that no
    the Florida courts apply the more petitioner-friendly Chapman standard of whether the
    constitutional error is “harmless beyond a reasonable doubt.” See Pittman v. State, — So. 3d —,
    
    2011 WL 2566325
    , at *9 (Fla. June 30, 2011); Guzman v. State, 
    868 So. 2d 498
    , 507-08 (Fla.
    2003).
    28
    Moreover, Brecht applies in federal habeas regardless of whether or not the state court
    recognized the constitutional error and applied a Chapman analysis. Fry v. Pliler, 
    551 U.S. 112
    ,
    121–22, 
    127 S. Ct. 2321
    , 2328 (2007).
    52
    Brecht analysis is needed for Brady violations, for the Supreme Court has held that
    a showing of materiality under Brady necessarily establishes actual prejudice
    under Brecht.29 Kyles v. Whitley, 
    514 U.S. 419
    , 435, 
    115 S. Ct. 1555
    , 1566
    (1995). In Kyles, the Supreme Court explained that the Brady materiality standard
    “impose[s] a higher burden on the [criminal] defendant” than the Kotteakos
    standard that the Court adopted for habeas review in Brecht. 
    Kyles, 514 U.S. at 436
    , 115 S. Ct. at 1567; see also 
    id. (noting that
    materiality test for Brady claims
    “would recognize reversible constitutional error only when the harm to the
    defendant was greater than the harm sufficient for reversal under Kotteakos”). In
    other words, a Brady error cannot be harmless under Brecht because “‘a
    reasonable probability that, had the evidence been disclosed to the defense, the
    result of the proceeding would have been different’ necessarily entails the
    conclusion that the suppression must have had ‘substantial and injurious effect or
    influence in determining the jury’s verdict.’” 
    Id. at 435,
    115 S. Ct. at 1566
    (quotation marks and citation omitted).
    29
    As mentioned above, Giglio error is a species of Brady error. But when we refer here to
    “Brady violations,” we mean Brady violations that are not Giglio violations. These non-Giglio
    Brady violations are sometimes referred to as Bagley violations or Brady/Bagley violations, after
    United States v. Bagley, 
    473 U.S. 667
    , 
    105 S. Ct. 3375
    (1985), which established the “reasonable
    probability that the result of the proceeding would have been different” materiality standard used
    for Brady violations that do not involve the knowing use of or failure to correct perjured
    testimony. See Kyles v. Whitley, 
    514 U.S. 419
    , 432–43, 
    115 S. Ct. 1555
    , 1565–66 (1995)
    (discussing Brady and its progeny, including Bagley).
    53
    But the more lenient Giglio materiality standard leaves room for the
    possibility that perjured testimony may be material under Giglio but still be
    harmless under Brecht. See Guzman 
    II, 663 F.3d at 1355
    –56 (finding Giglio
    violation and then applying Brecht standard to determine whether error was
    harmless); see also Rosencrantz v. Lafler, 
    568 F.3d 577
    , 584 (6th Cir. 2009)
    (“[W]hile a traditional Brady materiality analysis obviates a later harmless-error
    review under Brecht v. Abrahamson, courts may excuse []Giglio violations
    involving known and materially false statements as harmless error.”); Gilday v.
    Callahan, 
    59 F.3d 257
    , 268 (1st Cir. 1995) (“Applying [the Giglio materiality]
    standard in most cases involving perjury or its equivalent will likely result in a
    finding of constitutional error. Scaling that lower materiality hurdle, however, still
    will leave the petitioner facing the Brecht harmless error inquiry into whether the
    perjured testimony in fact had a substantial and injurious effect or influence on the
    jury’s verdict. In other words, . . . it is quite possible to find a constitutional
    violation, but to conclude that it was harmless.” (footnote omitted)).
    We have held that the Giglio materiality standard is equivalent to the
    Chapman “harmless beyond a reasonable doubt” test. 
    Ventura, 419 F.3d at 1279
    n.4. And, as the Supreme Court made clear in Brecht, the “substantial and
    injurious effect or influence” test is more onerous (from the criminal
    54
    defendant/habeas petitioner’s point of view) than the Chapman standard. Brecht,
    507 U.S. at 
    623, 113 S. Ct. at 1714
    . Thus, while a Brady error can never be
    harmless under Brecht because of Brady’s higher materiality standard, a Giglio
    error can be harmless under Brecht because the Giglio materiality standard is
    lower than that of Brecht.
    In short, we cannot grant federal habeas relief to Trepal unless (1) he shows
    that Martz’s false testimony violated Giglio, and (2) we find that the Giglio error
    was not harmless under Brecht.30 Because the Brecht harmlessness standard is
    more strict from a habeas petitioner’s perspective than the Giglio materiality
    standard, federal courts confronted with colorable Giglio claims in § 2254
    petitions in many cases may choose to examine the Brecht harmlessness issue first.
    We choose to do so here.
    We therefore ask whether, assuming Martz’s false testimony violated
    Giglio, was the Giglio error harmless under the standard set forth in Brecht.
    D.     Brecht Analysis
    Again, the Brecht test for actual prejudice is whether the constitutional error
    30
    As explained above, Trepal must also show that the Florida Supreme Court’s denial of
    his Giglio claim in Trepal II was contrary to Giglio, involved an unreasonable application of
    Giglio, or was based on an unreasonable determination of the facts in light of the evidence
    presented in state court. See 28 U.S.C. § 2254(d). But we assume, but do not decide, for
    purposes of this opinion that Trepal has satisfied those threshold requirements of § 2254(d).
    55
    “had substantial and injurious effect or influence in determining the jury’s
    verdict.” Brecht, 507 U.S. at 
    623, 113 S. Ct. at 1714
    . “To show prejudice under
    Brecht, there must be more than a reasonable possibility that the error contributed
    to the conviction or sentence.” Mansfield, slip op. at 27 (quoting Mason v. Allen,
    
    605 F.3d 1114
    , 1123 (11th Cir. 2010)). To determine the effect on the verdict of a
    constitutional error, the Court must consider the error “in relation to all else that
    happened” at trial. 
    Kotteakos, 328 U.S. at 764
    , 66 S. Ct. at 1248. The question
    turns on whether the Court can “say, with fair assurance,” that the verdict “was not
    substantially swayed by the error”:
    If, when all is said and done, the [court’s] conviction is sure that the
    error did not influence the jury, or had but very slight effect, the verdict
    and the judgment should stand . . . . But if one cannot say, with fair
    assurance, after pondering all that happened without stripping the
    erroneous action from the whole, that the judgment was not substantially
    swayed by the error, it is impossible to conclude that substantial rights
    were not affected. The inquiry cannot be merely whether there was
    enough to support the result, apart from the phase affected by the error.
    It is rather, even so, whether the error itself had substantial influence. If
    so, or if one is left in grave doubt, the conviction cannot stand.
    
    O’Neal, 513 U.S. at 437
    –38, 115 S. Ct. at 995 (quoting 
    Kotteakos, 328 U.S. at 764
    –65, 66 S. Ct. at 1248) (brackets and ellipsis in O’Neal) (emphasis omitted).
    The Brecht standard “does not require a showing that but for the error the
    jury would have rendered a verdict in favor of the defendant.” Duest v. Singletary,
    56
    
    997 F.2d 1336
    , 1338 (11th Cir. 1993). Nor does it matter whether the reviewing
    court believes the petitioner is guilty, for the “crucial thing is the impact of the
    thing done wrong on the minds of [the jurors] . . . in the total setting.” Id. (quoting
    
    Kotteakos, 328 U.S. at 764
    , 66 S. Ct. at 1247–48). But although the Brecht
    harmless error analysis “is necessarily fact-specific and must be performed on a
    case-by-case basis, the erroneous admission of evidence is likely to be harmless
    under the Brecht standard where there is significant corroborating evidence, or
    where other evidence of guilt is overwhelming.” Mansfield, slip op. at 27–28
    (citations omitted).
    With this framework in mind, we consider the impact of Martz’s false
    testimony on the verdict. When we do so, we readily conclude that the challenged
    portions of Martz’s testimony did not have a substantial and injurious effect or
    influence in determining the jury’s guilty verdict. Thus, any assumed Giglio error
    was harmless.
    First, we note that Trepal’s is not a typical Giglio claim. Usually (indeed, in
    every Giglio case in the Supreme Court or in this Court of which we are aware), a
    witness at trial gives testimony that is later shown to be demonstrably factually
    false. Here, by contrast, Trepal’s core Giglio allegation is that Martz gave his
    opinion at trial—that thallium nitrate was added to the Coca-Cola in samples Q1,
    57
    Q2, and Q3—and that opinion was held and testified to with more strength than
    what his data supported, but it has not been shown to be incorrect as a matter of
    fact. No one has shown either at trial or in postconviction proceedings that
    thallium nitrate was not added to the Coca-Colas, or that some form of thallium
    other than thallium nitrate was added to the Coca-Colas. At the 3.850 evidentiary
    hearing, Martz held fast to his opinion that thallium nitrate was added, and
    Trepal’s own 3.850 experts Dulaney and Whitehurst could not rule out that
    possibility, but merely stated there was insufficient data to identify which thallium
    salt was added. And it was undisputed that thallium in any salt is a deadly poison
    and that the Carrs were poisoned with thallium. Accordingly, here the contention
    is just that Martz could not truthfully have testified that thallium nitrate is the form
    of thallium that was added, but only that his test results were consistent with
    thallium nitrate being the form that was added.
    Because the question we must answer is the influence on the jury of the
    false testimony, we focus on the nature of the falsity—here, the difference
    between what Martz’s testimony was and what it should have been. Specifically,
    as the Florida courts correctly found, Martz: (1) testified that a positive result on
    the DP test (that is, when added DP turns a solution blue) indicates the presence of
    a nitrate, when Martz should have said that it indicates the presence of an
    58
    oxidizing ion, of which nitrate is an example; (2) testified that he ran IC tests on
    Q1, Q2, and Q3, when he actually ran the IC test only on Q1 and Q2; (3) testified
    there was no nitrate present in unadulterated Coca-Cola, when he should have said
    that the DP test was negative but the IC indicated a nitrate could be present; (4)
    testified only as to the DP and IC tests, when actually he performed additional
    testing on the samples, though he did not rely on the other tests in forming his
    conclusion; and (5) testified that, as a result of his testing, he concluded that
    thallium nitrate was added to Q1, Q2, and Q3, when he should have testified that
    the tests results for Q1 and Q2 were consistent with the presence of thallium
    nitrate and the results for Q3 were consistent with the presence of thallium and an
    oxidizing ion, which could be a nitrate. Notably, Martz’s conclusion about the
    brown bottle Q206 that was found in Trepal’s garage—that it contained thallium I
    nitrate—is not challenged.
    The gap between what Martz did testify and what everyone agrees he
    truthfully could have testified is narrow. For the most part, the difference is that
    Martz’s testimony should have been more nuanced, more guarded, less absolute or
    certain. The exception is Martz’s positive assertion that he ran the IC test on all
    three samples Q1 through Q3, when in fact he did not run the IC test on Q3. But
    even so, the DP result on Q3 was still consistent with the proposition that thallium
    59
    nitrate was added to Q3; it just made that proposition less certain. And it hardly
    matters whether thallium nitrate was the form of thallium that was added to Q1,
    Q2, and Q3, as opposed to just Q1 and Q2.
    Furthermore, Martz’s testimony as a whole was just one small part of the
    State’s evidence against Trepal. Among other things, the State established with
    other witnesses, whose testimony stands unchallenged, that: (1) the Carr family
    was poisoned with thallium; (2) thallium was found in the full and empty Coca-
    Cola bottles in the Carrs’ home; (3) thallium is a rare and toxic element, and is
    difficult to obtain because the chemical companies that sell it do not sell to
    individuals; (4) a brown glass bottle containing thallium was found in Trepal’s
    Alturas garage; (5) when moving into his Alturas home in 1982, Trepal had
    chemicals in brown glass bottles and said he intended to set up a chemistry
    laboratory in his garage; (6) Trepal had an extensive knowledge of chemistry and a
    collection of chemistry paraphernalia, including glassware, bottles of toxic
    chemicals, and books that discussed thallium; (7) Trepal had a homemade journal
    on poisons and poison detection; (8) Trepal’s poison journal bore his fingerprints
    and contained photocopies from a library book belonging to the college Trepal
    attended in the 1970s, suggesting the journal pre-dated the Carr poisonings; (9)
    Trepal was the chemist for a methamphetamine production ring, and thallium is
    60
    sometimes used in methamphetamine production; (10) Trepal did not get along
    with any of the members of the Carr family, and he still exhibited anger and
    animosity after the poisonings about incidents that had happened years earlier;
    (11) Trepal repeatedly threatened the Carr children, and once said he would kill
    them; (12) Trepal’s conflicts with the Carrs continued well into 1988, the year of
    the poisonings; (13) in the middle of 1988, the Carrs received an anonymous letter
    warning the whole Carr family that they would all die unless they moved away;
    (14) Trepal and his wife were the Carrs’ only neighbors; (15) Trepal wrote a
    Mensa “murder mystery weekend” pamphlet that discussed poisoning and a
    “move-or-else” note left on a neighbor’s doorstep; and (16) Trepal’s explanation
    for the Carr poisonings was “to get them to move out, like they did.”
    Amid the breadth and depth of this evidence, Martz (who was one of more
    than 70 witnesses during the State’s case) testified to one discrete issue: the
    comparison of (1) the substance added to the full Coca-Cola bottles Q1 through
    Q3, with (2) the substance found in the brown bottle Q206. The State had already
    established through expert Havekost (whose work and testimony has not been
    challenged or disparaged in any way) that both substances were thallium
    compounds—that is, that thallium was found in Q1–Q3 and in Q206. Thallium in
    any form is rare enough, as the State pointed out to the jury in its closing
    61
    argument. Martz just further added to an already tight link by opining that the
    Q1–Q3 bottles and the Q206 bottle all contained the same form of
    thallium—which was thallium nitrate.31 There was no evidence at all from any
    witness or source that the Q1–Q3 samples and the Q206 bottle contained different
    forms of thallium.
    To be sure, Martz was an important witness for the State’s case, as his
    testimony went to the identification of the potential murder weapon (the substance
    in Q206), which was the piece of physical evidence linking Trepal to thallium.
    But Martz’s testimony that Q206 contained thallium I nitrate is not challenged.
    And the other permissible testimony from Martz was highly incriminating, such as
    that the Q1 and Q2 samples were consistent with the presence of thallium nitrate.
    In any event, Martz’s testimony about the samples from the Q1 through Q3
    Coca-Cola bottles—even to the extent it was overly strong in its conclusions—did
    not, and could not, establish conclusively that the substance that had been added to
    the Carrs’ Coca-Colas had come from the Q206 bottle.32 Even without Martz’s
    31
    To illustrate, if this case were a hit-and-run by a rare automobile instead of murder by a
    rare poison, Havekost established, say, that the victims were hit by, and the defendant owned, a
    red Ferrari. Martz narrowed it down to a 1982 red Ferrari, but still no one could match the
    license plates.
    32
    The State acknowledged this point in its closing argument, stating, “Nobody can tell you
    that this thallium nitrate is the thallium nitrate that was in those bottles because it’s just thallium
    nitrate.” The State analogized to table salt dropped on a rug, noting that no crime scene
    62
    testimony, Q206’s linkage of Trepal to thallium was just as strong, for Martz
    neither found the Q206 bottle in Trepal’s garage (Brekke did) nor found that it
    contained thallium (Havekost did). As we have pointed out, thallium in any form
    is a rare and deadly poison.
    The portion of Martz’s testimony that was challenged was just one narrow
    part of the State’s strong case against Trepal, and any falsities in Martz’s
    testimony were narrower still. Although Trepal belittles the abundant evidence
    against him at trial, the Florida courts properly characterized the totality of the
    evidence as “strong.” See Trepal 
    II, 846 So. 2d at 426
    (“Although this is a
    circumstantial evidence case, the evidence was strong.” (quoting 3.850 court)).
    In sum, we are convinced that, if any falsities in Martz’s testimony had any
    effect at all upon the jury’s verdict, it was very slight. Martz’s improper testimony
    certainly did not have, as the Brecht test requires, “a substantial and injurious
    effect or influence in determining the jury’s verdict.” 
    Brecht, 507 U.S. at 623
    , 117
    S. Ct. at 1714. We are convinced of that. Thus, even assuming arguendo that
    Trepal could establish a Giglio violation, we conclude that it was harmless.
    technician in the world could tell whether a grain of table salt on the rug came from a particular
    bottle of salt or if it was already on the floor. Trepal’s attorney Wofford Stidham also made this
    point in his closing argument for Trepal, arguing, “[D]id the thallium in the Coca-Colas come
    from this little bottle? The innuendo was there that it did. You heard the witness this very
    morning that was asked that question, could he say the thallium in the Coca-Cola came from that
    little bottle and he said no. You have to speculate.”
    63
    Accordingly, Trepal is not entitled to habeas relief.
    IV. CONCLUSION
    We affirm the district court’s denial of Trepal’s § 2254 petition.
    AFFIRMED.
    64
    PRYOR, Circuit Judge, concurring:
    I concur in the panel opinion because I agree that George Trepal is not
    entitled to habeas relief and that any error under Giglio v. United States, 
    405 U.S. 150
    , 
    92 S. Ct. 763
    (1972), that occurred during Trepal’s trial was harmless. I write
    separately to explain why the adjudication of Trepal’s Giglio claim by the
    Supreme Court of Florida is also entitled to deference under Antiterrorism and
    Effective Death Penalty Act, 28 U.S.C. § 2254(d). The Supreme Court of Florida
    did not apply an incorrect standard in its adjudication of Trepal’s Giglio claim.
    Nor did the Florida circuit court apply an incorrect standard in its adjudication of
    Trepal’s Giglio claim. Either decision is entitled to deference under section
    2254(d), and neither decision involves an unreasonable application of clearly
    established federal law.
    A. Nothing in the Analysis by the Supreme Court of Florida Suggests that the
    Court Incorrectly Identified the Standard Applicable to Trepal’s Giglio Claim or
    Applied the Incorrect Standard in Its Adjudication of Trepal’s Giglio Claim.
    Trepal argues that the Supreme Court of Florida conflated the Giglio and
    Brady standards of materiality in evaluating his Giglio claim, but there is nothing
    in the analysis of his claim by that court to support his assertion. See Trepal v.
    State, 
    846 So. 2d 405
    , 426–28 (Fla. 2003) (Trepal II). The Supreme Court of
    Florida never articulated the materiality standard that it purported to apply in its
    65
    adjudication of Trepal’s claim, and its analysis gives little insight into which
    standard it actually applied in its adjudication of that claim. See 
    id. “Where the
    standards utilized by the state court are not articulated,” we “may properly assume
    that the state [court] applied correct standards of federal law . . . in the absence of
    evidence . . . that an incorrect standard was in fact applied.” Demps v.
    Wainwright, 
    805 F.2d 1426
    , 1434 (11th Cir. 1986) (internal quotation marks
    omitted). The only discussion of the Giglio and Brady standards in the opinion by
    the Supreme Court of Florida appears in a section labeled “Circuit Court’s
    Analysis” and is a direct quote from the opinion by the state circuit court. See
    Trepal 
    II, 846 So. 2d at 423
    –25. The Supreme Court of Florida neither repeated
    nor otherwise adopted, in the section of its opinion labeled “This Court’s
    Analysis,” the statements by the circuit court regarding the Giglio and Brady
    standards. See 
    id. at 426–28.
    The Supreme Court of Florida approved the factual
    findings of the circuit court and agreed with the conclusion by the circuit court
    “that Trepal was not impermissibly prejudiced by the testimony of Martz,” see 
    id., but the
    Supreme Court of Florida never stated its standard for determining
    prejudice.
    Nor do statements that the Supreme Court of Florida made in other opinions
    that adjudicated other petitioners’ Giglio claims prove that the court applied the
    66
    wrong standard in adjudicating Trepal’s Giglio claim. The relevant decision for
    our analysis under section 2254(d) is the decision that adjudicated Trepal’s claim,
    not the decisions in other appeals. See 28 U.S.C. § 2254(d) (precluding federal
    habeas relief based upon “any claim that was adjudicated on the merits in State
    court proceedings unless the adjudication of the claim” satisfies certain
    requirements) (emphasis added). The relevance to our inquiry of any decision by
    the Supreme Court of Florida before that court adjudicated Trepal’s claim is not
    readily apparent, especially when that court did not cite any of those decisions in
    its analysis of Trepal’s claim, see Trepal 
    II, 846 So. 2d at 426
    –28. Cf. 
    Ventura, 419 F.3d at 1283
    (considering the conclusions of law articulated in decisions cited
    by a state court in its own opinion). Although the Supreme Court of Florida
    erroneously suggested that the Brady and Giglio standards were equivalent in
    several opinions issued between 1991 and 2000, see, e.g., Rose v. State, 
    774 So. 2d
    629, 635 (Fla. 2000), the opinion in Ventura v. State reveals that the Supreme
    Court of Florida was aware of the distinction between the Brady and Giglio
    standards in 2001—well before it adjudicated Trepal’s claim in 2003. See
    Ventura v. State, 
    794 So. 2d 553
    , 563 (Fla. 2001) (quoting United States v. Alzate,
    
    47 F.3d 1103
    , 1109–10 (11th Cir. 1995)). It is likewise of little relevance to our
    inquiry that the Supreme Court of Florida “recede[d]” from Trepal II in a later
    67
    decision, “to the extent” that Trepal II stood “for the incorrect legal principle that
    the ‘materiality’ prongs of Brady and Giglio are the same,” because the court
    neither overruled Trepal II nor declared that Trepal II was intended to—or did in
    fact—stand for that principle. See Guzman v. State, 
    868 So. 2d 498
    , 505–06 (Fla.
    2003).
    B. Nothing in the Analysis by the Florida Circuit Court Suggests that the Court
    Incorrectly Identified the Standard Applicable to Trepal’s Giglio Claim or
    Applied the Incorrect Standard in Its Adjudication of Trepal’s Giglio Claim.
    Even if the Supreme Court of Florida had adopted the analysis that appears
    in the section of its opinion labeled “Circuit Court’s Analysis,” the Supreme Court
    of Florida would not have applied the incorrect standard in its adjudication of
    Trepal’s Giglio claim. The Supreme Court of the United States has made clear
    that we must “presum[e] that state courts know and follow the law,” and give state
    court decisions “the benefit of the doubt,” Woodford v. Visciotti, 
    537 U.S. 19
    , 24,
    
    123 S. Ct. 357
    , 360 (2002). Nothing in the portion of the analysis by the circuit
    court that appears in the opinion by the Supreme Court of Florida is sufficient to
    overcome the presumption that the Florida courts applied the correct standard in
    their adjudication of Trepal’s Giglio claim.
    The circuit court correctly articulated the Giglio standard for materiality in
    its explanation of Trepal’s Giglio claim. See Trepal 
    II, 846 So. 2d at 425
    . The
    68
    formulation of the standard by the circuit court deviated only slightly from the
    formulation favored by the Supreme Court in that the circuit court used “a” instead
    of “any” and “jury verdict” instead of “judgment of the jury,” but neither of those
    minor inconsistencies could have had any effect on the analysis of Trepal’s claim.
    This Court has held that the substitution of “a” for “any” is “of no consequence” in
    the articulation of the Giglio standard. See 
    Ventura, 419 F.3d at 1282
    . There also
    is no relevant distinction between “jury verdict” and “judgment of the jury,” as
    both refer to the jury’s “decision” on the issue of the defendant’s guilt. See
    Oxford English Dictionary (2d ed. 1989); accord Black’s Law Dictionary (9th ed.
    2009).
    Although the circuit court incorrectly stated that “[t]he materiality prong
    [used in Giglio] is the same as that used in Brady,” Trepal 
    II, 846 So. 2d at 425
    ,
    this single misstatement is “insufficient” to support the conclusion that the circuit
    court applied the wrong standard in its adjudication of Trepal’s claim. Cf.
    
    Ventura, 419 F.3d at 1285
    –86. The circuit court offered no explanation of the
    Brady materiality standard, but articulated the Giglio materiality standard in terms
    that closely approximate those used by the United States Supreme Court.
    Compare 
    id. (observing that
    false testimony is “material if there is a reasonable
    likelihood that it could have affected the jury verdict”) (internal quotation marks
    69
    omitted), with United States v. Agurs, 
    427 U.S. 97
    , 103, 
    96 S. Ct. 2392
    , 2397
    (1976) (observing that false testimony is material “if there is any reasonable
    likelihood that the false testimony could have affected the judgment of the jury”).
    That the circuit court explained the Giglio standard and not the Brady standard
    suggests that, if the circuit court believed that the same standard applied to both
    Giglio and Brady claims, then that so-called “same” standard was the Giglio
    standard. In that case, the circuit court applied the correct standard to Trepal’s
    Giglio claim.
    The circuit court also applied the Giglio standard using correct terminology.
    After the circuit court correctly articulated the Giglio standard at the beginning of
    its discussion of Trepal’s Giglio claim, see Trepal 
    II, 846 So. 2d at 425
    , the circuit
    court ruled “that there [was] no reasonable likelihood that the verdict would have
    been different” in either the guilt phase or the penalty phase of Trepal’s trial had
    Martz not testified falsely, 
    id. at 426.
    Trepal contends that the circuit court
    misapplied the Giglio standard when it used the term “would” instead of “could,”
    but that argument fails. The conclusion of the circuit court that “there [was] no
    reasonable likelihood that the verdict would have been different” in the absence of
    Martz’s false testimony, 
    id. at 426,
    is a satisfactory response to the question
    whether there was “any reasonable likelihood that the false testimony could have
    70
    affected the judgment of the jury,” 
    Agurs, 427 U.S. at 103
    , 96 S. Ct. at 2397. As a
    matter of logic, when answering the question posed by the Giglio standard, saying
    that there is no reasonable likelihood that the verdict would have been different is
    the same as saying that there is no reasonable likelihood that the verdict could
    have been different. This Court too has used the term “would” in applying the
    Giglio standard to reach the conclusion that false testimony did not satisfy that
    standard. Sitting en banc in McCleskey v. Kemp, an appeal from a grant of habeas
    corpus relief, this Court correctly stated that false testimony is material under the
    Giglio standard if “it could ‘in any reasonable likelihood have affected the
    judgment of the jury.’” 
    753 F.2d 877
    , 885 (11th Cir. 1985) (en banc) (quoting
    Giglio v. United States, 
    405 U.S. 150
    , 154, 
    92 S. Ct. 763
    , 766 (1972)). We then
    applied the standard and, like the Florida circuit court that adjudicated Trepal’s
    claim, concluded that the false testimony at issue was not material because it
    “would have had no effect on the jury’s decision.” 
    Id. (emphasis added).
    We
    reversed the grant of habeas corpus relief as to the petitioner’s Giglio claim. 
    Id. We cannot
    fault the circuit court for applying the Giglio standard using the same
    language that we have used when we have applied it.
    C. Neither the Supreme Court of Florida Nor the Florida Circuit Court
    Unreasonably Applied Clearly Established Federal Law in Its Adjudication of
    Trepal’s Giglio Claim.
    71
    Neither the Supreme Court of Florida nor the Florida circuit court
    unreasonably applied the Giglio standard of materiality to Trepal’s Giglio claim
    when those courts determined that there was no reasonable likelihood that Martz’s
    false testimony could have affected the judgment of the jury at Trepal’s trial, see
    Trepal 
    II, 846 So. 2d at 425
    –28. Martz’s testimony was useful only to establish
    the particular type of thallium in the three full bottles of Coca-Cola taken from the
    Carr residence and the glass bottle taken from Trepal’s garage. The government
    established through other witnesses that thallium in any form is rare and
    unavailable to the general public and that thallium in some form had been added to
    the three bottles taken from the Carr residence and was contained in the glass
    bottle taken from Trepal’s garage. Fairminded jurists considering this
    unchallenged testimony in combination with the wealth of unchallenged
    circumstantial evidence of Trepal’s guilt presented at trial could disagree whether
    Martz’s false testimony could have affected the judgment of the jury at Trepal’s
    trial. Cf. Yarborough v. Alvarado, 
    541 U.S. 652
    , 664, 
    124 S. Ct. 2140
    , 2149
    (2004). That “fairminded jurists could disagree on the correctness of the state
    court[s’] decision[s]” means that we cannot grant Trepal federal habeas relief on
    the basis of his Giglio claim. Harrington v. Richter, 562 U.S. ----, 
    131 S. Ct. 770
    ,
    786 (2011).
    72