                 FOR PUBLICATION

  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT


JOSEPH P. SHELTON,                         No. 13-15707
                          Petitioner,
                                             D.C. No.
                 v.                       4:10-cv-01100-
                                               PJH
JOHN C. MARSHALL; ATTORNEY
GENERAL OF THE STATE OF
CALIFORNIA,                                 OPINION
            Respondents-Appellees.


     Appeal from the United States District Court
          for the Northern District of California
   Phyllis J. Hamilton, Chief District Judge, Presiding

       Argued and Submitted November 20, 2014
        Submission Vacated November 25, 2014
              Submitted August 7, 2015
               San Francisco, California

                  Filed August 7, 2015

  Before: Sidney R. Thomas, Chief Judge and Stephen
    Reinhardt and Morgan Christen, Circuit Judges.

              Opinion by Judge Reinhardt
2                    SHELTON V. MARSHALL

                           SUMMARY*


                          Habeas Corpus

     The panel reversed in part and affirmed in part the district
court’s denial of California state prisoner Joseph Shelton’s
habeas corpus petition challenging his convictions for the
first-degree murder of Kevin Thorpe, the second-degree
murder of Laura Craig, kidnapping, and theft.

    The panel held that the prosecution’s suppression of a
material part of its deal with key witness Norman Thomas
violated Brady v. Maryland with respect to Shelton’s
conviction for the first-degree murder of Thorpe, and ordered
the writ granted as to that conviction. The panel explained
that Thomas’s testimony was central to the prosecution’s case
that Shelton premeditated and deliberated regarding Thorpe’s
murder, and held that there is a reasonable probability that
had the jury known of the prosecution’s serious doubts as to
Thomas’s mental competence and of its successful efforts to
prevent him from obtaining a competency test until after he
testified, it would have reached a different result on that
count. The panel concluded, in a memorandum disposition,
that had Thomas been impeached by evidence of the secret
deal with the prosecution regarding his competency, there is
not a reasonable probability that the jury would have reached
a different result with respect to Shelton’s convictions for the
second-degree murder of Craig, kidnapping, and theft.




  *
    This summary constitutes no part of the opinion of the court. It has
been prepared by court staff for the convenience of the reader.
                  SHELTON V. MARSHALL                       3

                        COUNSEL

William L. Osterhoudt (argued) and Dolores T. Osterhoudt,
Law Offices of William L. Osterhoudt, San Francisco,
California, for Petitioner-Appellant.

Peggy S. Ruffra (argued), Supervising Deputy Attorney
General; Kamala Harris, Attorney General; Dane R. Gillette,
Chief Assistant Attorney General; Gerald A. Engler, Senior
Assistant Attorney General; Christopher J. Wei, Deputy
Attorney General, San Francisco, California, for Respondent-
Appellee.


                         OPINION

REINHARDT, Circuit Judge:

    Joseph Shelton, who is serving 40 years to life for the
brutal kidnapping and murder of Kevin Thorpe and Laura
Craig in 1981, appeals from the denial of his petition for a
writ of habeas corpus. We hold that the prosecution’s
suppression of a material part of its deal with a key witness,
Norman Thomas, violated Brady v. Maryland, 373 U.S. 83
(1963), with respect to Shelton’s conviction for the first-
degree murder of Thorpe and order the writ granted as to that
conviction. Thomas’s testimony was central to the
prosecution’s case that Shelton premeditated and deliberated
regarding Thorpe’s murder, and there is accordingly a
reasonable probability that had the jury known of the
prosecution’s serious doubts as to Thomas’s mental
competence and of its successful efforts to prevent him from
obtaining a competency test until after he testified, it would
have reached a different result on that count. We conclude,
4                 SHELTON V. MARSHALL

however, in a memorandum disposition filed along with this
opinion that, had Thomas been impeached by evidence of the
secret deal with the prosecution regarding his competency,
there is not a reasonable probability that the jury would have
reached a different result with respect to Shelton’s
convictions for the second-degree murder of Craig,
kidnapping, and theft. Thus, we affirm as to those counts.

                       I. Background

    A. The offenses and trials

    Shelton stands convicted of the first-degree murder of
Thorpe, the second-degree murder of Craig, two counts of
kidnapping, two counts of theft, and two weapons charges.
Most of the basic facts are undisputed. On January 11, 1981,
Thorpe and Craig were driving through Madeline, California
on the way to college when Shelton, Thomas, and Benjamin
Silva spotted them at a gas station and subsequently abducted
them. The three men took the couple to Shelton’s cabin,
where Thorpe was chained to a tree while Craig was held
inside.

   The next day, Thorpe was shot to death with a machine
gun. At Silva’s direction, Thomas dismembered Thorpe’s
body and the two men disposed of it in a remote location.
Craig was murdered on the side of the road a few days later.
She had been shot twice.

    Thomas was subsequently arrested for a probation
violation. While in custody, Thomas told the police about the
murders and directed them to Thorpe’s remains and other
physical evidence of the crimes. Shelton turned himself in
shortly thereafter, waived his rights, and gave a series of
                       SHELTON V. MARSHALL                                 5

partially inculpatory though sometimes inconsistent
statements to the police. He also led them to Craig’s remains.

    At Shelton’s trial, the State’s evidence consisted primarily
of Thomas’s testimony, Shelton’s own statements to
investigators, and a series of notes passed between Shelton
and Thomas while the two were in jail.1 The defense case
consisted of Shelton’s testimony that he had been present
during the crimes but that he was intoxicated on various drugs
and alcohol, did not willingly participate, and feared that if he
resisted or tried to leave, Silva would kill him and his family.2
There was thus no dispute that Shelton was at least present
for all of the crimes. At issue with respect to Thorpe’s
murder—the only question we deal with in this opinion—is
the degree of Shelton’s participation and whether he
possessed the requisite mens rea, i.e, whether he “deliberated
and premeditated” as required by California law for a
conviction of first-degree murder. See infra note 13.

    At trial, Thomas and Shelton testified to different versions
of the crimes. In both versions, Silva was the primary
instigator. Their testimony differed greatly, however,

   1
     The jury also heard testimony about the scene of the crimes, the
condition of the bodies, the property of the victims that was recovered, the
weapons and other items found in the cabin and the surrounding area, and
the local geography. None of this evidence conveyed anything about
Shelton’s particular role in the crimes, with the exception of testimony that
Shelton’s fingerprints were found on a car stereo taken from the victims’
car and on sundry items in the cabin, and that he was wearing Thorpe’s
boots when he turned himself in. None of this testimony shed any light on
the question whether Shelton was guilty of first-degree deliberate and
premeditated murder.
  2
    At the time of the crimes, Silva was a Hell’s Angel and a fugitive.
Shelton and Thomas’s relationships to the Angels was less clear.
6                 SHELTON V. MARSHALL

regarding the degree of Shelton’s participation. According to
Shelton, when Silva spotted the couple at the gas station and
proposed kidnapping them, Shelton said that he “didn’t want
no part of it.” He initially denied that the men had discussed
kidnapping and killing people before they saw Thorpe and
Craig, but when his recollection was refreshed with a copy of
a statement he gave to an investigator the day after he turned
himself in, he admitted that the three men had discussed
kidnapping a girl a few weeks before the crimes.

    A few miles past the gas station, Silva used a red light to
pull the couple’s car over. Shelton testified that he was with
Silva when he purchased a light like the one used, but that it
was purchased for an unrelated prank and he never held it
during the kidnapping. Once the victims’ car stopped, Silva
and Thomas ran up to it, entered it, and abducted the couple
at gunpoint. Shelton remained in the truck in which the three
men had arrived and followed the couple’s car to his cabin;
he testified that he did not drive off because he believed that
“Silva would have killed me. . . . He would have killed my
family.” When they arrived at Shelton’s property, Silva told
Craig and Thorpe to get on the back of the truck, which
Shelton then drove to the cabin. Shelton then remained at the
cabin with Craig, Thorpe, and Silva, while Thomas left for a
short period. When Thomas returned, he and Silva took
Thorpe outside, and he later told Shelton that they had
chained Thorpe to a tree. Silva and Thomas then left until
morning. While they were gone, Shelton gave Thorpe a
sleeping bag.

    Shelton testified that after Silva and Thomas returned the
next day, Silva “said he was moving [Thorpe] because he
could be seen from the road.” Shelton, who said that he
believed that he was unarmed, stated that he then walked with
                   SHELTON V. MARSHALL                         7

Thorpe, who was still chained, up a hill, while “[Silva] took
off . . . to get . . . some more chain and stuff.” Shelton denied
knowing that Thorpe was being taken up the hill to be killed,
and said that he did not speak to Thorpe while they waited
“not [a] very long” time before Silva returned. Shelton
testified that when Silva returned, he “heard a click and . . .
turned around and [Silva] was standing there with a machine
gun;” Shelton said he was halfway between Silva and Thorpe
and “jumped behind a tree when the bullets started flying.”
After Silva emptied a clip (thirty bullets) into Thorpe, Shelton
said that Thorpe fell to the ground, and then Silva fired half
of another clip into him. According to Shelton, Silva then
“gave [Shelton] the gun and said shoot him.” Shelton
admitted that he then fired the rest of the clip at Thorpe, but
stated that he didn’t think that he hit him and that he “wasn’t
aiming at him.” He said that although he had previously told
police that he hit Thorpe in the eye, “that was something that
stuck in my mind from something else.” Shelton stated that
if he hadn’t shot at Thorpe, Silva would have killed him “the
second I said no.”

     Shelton testified that in the days following Thorpe’s
murder, he tried to protect Craig from Silva. He said that at
one point he left the cabin with her and that they ran across a
meadow and over a hill “when [Silva] caught us.” He also
stated that he thought that he could talk Silva out of killing
Craig, that at one point he had in fact talked Silva out of
killing her, that Craig liked Shelton more than the others and
was not afraid of him, and that she could have left at any
time. He denied knowing that she would be killed when he
and Silva left the cabin with her, purportedly to take her to
see the head of the Hell’s Angels. Shelton stated that Silva
stopped along the way to buy Craig a Pepsi and that Silva was
very calm, leading him to believe that he would not shoot her.
8                 SHELTON V. MARSHALL

Silva later stopped the truck to change drivers but then
suddenly shot Craig as he rounded the vehicle. Finally,
Shelton testified that he was on speed, “reds, valium, and pot”
the night of the kidnapping but that he was not intoxicated
when Craig was killed.

    Thomas’s testimony about Shelton’s role in the crimes
differed considerably. In his account, none of the men
consumed any alcohol or drugs during the course of the
criminal activities. According to Thomas, Shelton and Silva
had discussed kidnapping people prior to the crimes and said
that if they did so, they would have to kill them. At the
Madeline gas station, Silva said he “wanted” Craig, and
Shelton remarked that she was pretty. Just prior to the
kidnapping, Thomas and Shelton swapped positions in the
truck after Shelton declined to do the kidnapping because he
was too well known in the area.

    Thomas testified that it was Shelton and Silva who
chained Thorpe to the tree outside of the cabin, that it was
Thomas who gave him a sleeping bag, and that Shelton
became upset when Craig was left unguarded. With respect
to Thorpe’s murder, Thomas testified that Shelton was armed
when he left with Silva and Thorpe to go up the hill, that
Shelton returned and told Thomas to turn on the stereo, and
that Silva later returned and told him to turn up the
volume—the inference being that they wanted to mask the
sound of gunfire.

    According to Thomas, Shelton later confessed his role in
Thorpe’s murder to Thomas, stating that he had watched
Thorpe while Silva went to get a machine gun; that Thorpe
cried and asked to be unchained; and that while waiting for
Silva, Shelton told Thorpe “to look at the mountain, because
                      SHELTON V. MARSHALL                                9

it was the last thing he would see.” Thomas also said that
Shelton told him that Thorpe’s arm was reaching up after
Silva emptied the first clip into him, that Silva then shot him
again, and that then “[Shelton] took the machine gun and shot
the guy all over again.” Finally, Thomas testified that Shelton
laughed as he recounted the murder to him.

    The jury also heard testimony regarding incriminating
statements that Shelton made to various law enforcement
officials after turning himself in, both via the reading of
transcripts and officer testimony.3 In interviews on January
31, 1981 and February 1, 1981, Shelton professed to have
been intoxicated during the kidnapping, yet recounted details
of the events, including that the men discussed kidnapping a
female before the abduction. According to this testimony, he
also stated that he was armed during the initial kidnapping,
that he had sex with Craig in the cabin but that, unlike when
Silva and Thomas had sex with her, his sexual acts were not
forcible.4

   During the initial interviews on January 31 and February
1, Shelton claimed that he was not present for Thorpe’s
murder and that he learned about it from Thomas. A sergeant


   3
      The jury heard (or was read): (1) a transcript of an interview on
January 31, 1981; (2) testimony from Sergeant Coulter of the Shasta
County Sheriff’s Office about interviews on February 1, 1981 and
February 2, 1981; (3) a transcript of an interview on February 2, 1981; and
(4) testimony from an investigator for the California Department of Justice
about an unrecorded interview with Shelton on February 3, 1981.
  4
    On January 31, Shelton stated in a recorded interview that he was
“always armed” during this period in which the crimes took place. On
February 3, he said he might have been armed during the kidnapping but
wasn’t sure.
10                 SHELTON V. MARSHALL

testified that Shelton stated that while he was inside the cabin
with Craig, “Mr. Thomas and Silva came in and told him to
turn the music up on the stereo. And a little later they came
back and told him to turn it up a little louder.” The sergeant
also testified that Shelton said that before Silva and he left the
cabin with Craig, Silva told him he was going to kill her with
a baseball bat, and that Shelton “indicate[d] that he didn’t
believe she had any chance to escape or leave.” Shelton’s
account of Craig’s murder was otherwise consistent with his
account on the stand—that Silva stopped the car to switch
drivers, but then, without any indication of his intent to do so,
suddenly shot Craig.

    Shelton’s story regarding Thorpe’s murder changed
during interviews on February 2. He first denied being
present during Thorpe’s killing. Later, in interviews on that
day and the next, however, he admitted being present and
recounted the Thorpe killing consistently with his trial
testimony, except that he said nothing about what he thought
Silva was planning to do (either when they went up the hill or
when Silva left him with Thorpe) and he admitted that he
“might have” been armed at the time but wasn’t sure. In these
interviews, Shelton never gave any indication that he knew in
advance that Silva was planning to shoot Thorpe. At trial,
Shelton claimed that his story had changed from the initial
interviews because he had tried to block out the Thorpe
murder.

    During an interview on February 2, Shelton said that the
reason he at one point took Craig across a meadow and over
a hill was that he thought the Hell’s Angels were coming and
that he and Silva “hadn’t come to an agreement yet as to what
was going to happen to her.” He explained that they might
                      SHELTON V. MARSHALL                             11

make her “a prostitute, x-rated movie maker, club pass-
around” or someone’s “old lady.”

    An investigator with the California Department of Justice
testified, on the basis of the only unrecorded interview, that
on February 3, 1981, Shelton stated that prior to the
kidnapping, “there had been a conversation that if in fact [a]
kidnapping were to take place that they might have to kill the
victims”; that “Mr. Silva spoke of it on numerous occasions”;
and that Silva and Shelton had purchased the red light in
preparation for committing a kidnapping. The investigator
also testified that Shelton told him that when he and Silva left
the cabin with Craig, he was convinced that she would be
murdered—about 90% sure—but “felt by his being present
perhaps somewhat he could intercede and save her.”
Shelton’s statements on February 2 and 3 regarding Craig’s
murder were otherwise the same as at trial.

    The prosecution also introduced into evidence several
notes that Shelton wrote to Thomas while the two were in jail
subsequent to Shelton learning that Thomas was cooperating
with the prosecution and subsequent to all of Shelton’s
inculpatory statements to the police. The notes have no
bearing on the issue in this appeal, as they did not discuss
Thorpe’s murder or contain evidence of premeditation or
deliberation.5

 5
   For example, in one note Shelton told Thomas to tell his lawyer that he
decided to tell the truth because “Joe almost died last night, and was
refused medical attention, and you felt sorry for me.” In another note, he
told Thomas that “if the lawyer can’t get you off, I’ll break you out.” He
also said that Thomas should testify that Shelton received a ride from an
old cowboy after they saw the couple at the gas station and was not seen
again until the crimes were over. A third note told Thomas to start
attending bible study because it would help their case.
12                SHELTON V. MARSHALL

     On November 17, 1981, after deliberating for two and a
half days, the jury convicted Shelton of the first-degree
murder of Thorpe, the second-degree murder of Craig, two
counts of kidnapping, two counts of theft, possession of a
machine gun, possession of a silencer, and one special
circumstance with respect to the Thorpe murder, making
Shelton eligible for the death penalty. Significantly, the
verdict reflects that the jury acquitted Shelton of the charge
of first-degree murder of Craig. After the jury declined to
impose a capital sentence for Thorpe’s murder, the court
sentenced Shelton to life without parole on that charge and
fifteen years to life for Craig’s murder in the second degree
to be served consecutively. It stayed its sentences with
respect to the other counts. On June 27, 1984, the California
Court of Appeal affirmed the judgment but struck the special
circumstance in an unpublished opinion. Shelton was then
resentenced to twenty-five years to life for the murder of
Thorpe.

     Silva was tried after Shelton in January 1982. Thomas
was again the principal prosecution witness. Shelton was
called to testify, but invoked his Fifth Amendment privilege
against self-incrimination. See Silva v. Woodford (“Silva I”),
279 F.3d 825, 828 (9th Cir. 2002). Silva was convicted of the
first-degree murder of Thorpe, the kidnapping and theft of
both Thorpe and Craig, and possession of a machine gun and
silencer. Id. at 829. He was acquitted, however, of the murder
of Craig. He was then sentenced to death for the murder of
Thorpe. Id.

     B. The prosecution’s secret deal with Thomas

    In 1986, Silva’s counsel learned that before Shelton’s and
Silva’s trials, Thomas’s attorney, Rex Gay, approached
                  SHELTON V. MARSHALL                      13

Lassen County District Attorney Paul DePasquale, the
prosecutor in both cases, and “indicated . . . that [Gay]
believed that Mr. Thomas was either unable to cooperate in
his own defense, or insane.” Prior to this, Gay had also
obtained a protective order prohibiting the undersheriff from
speaking with Thomas “based on the belief that he was
incapable of understanding [his] rights.” Prior to the crimes,
Thomas had suffered a severe motorcycle accident resulting
in an extended coma, and Gay “noted a certain slowness in
his mannerisms and a defect in his speech pattern.” Gay told
DePasquale that he “had immediate plans to have [Thomas]
interviewed by two psychiatrists.”

    DePasquale agreed with Gay that he would be unable to
obtain a conviction of either Silva or Shelton without
Thomas’s cooperation. DePasquale and Gay also agreed that
a psychiatric analysis of Thomas would “supply ammunition
to the defense.” They then reached a plea agreement in which
Gay would refrain from having Thomas psychiatrically
examined, Thomas would testify against Shelton and Silva,
and DePasquale would drop murder charges against Thomas.
The portion of the deal pertaining to Thomas’s mental
competency was not disclosed to either Shelton or Silva.
Indeed, Shelton first learned about it when he read this
Court’s 2005 decision granting habeas relief to Silva.

   C. Subsequent procedural history

    In 2002, this Court, through a different panel of judges,
granted Silva’s habeas claim for penalty-phase ineffective
assistance of counsel and remanded for an evidentiary hearing
on a Brady claim based on the prosecution’s failure to
disclose the portion of the deal with Thomas relating to
14                    SHELTON V. MARSHALL

Thomas’s not undergoing a psychiatric examination.6 Id. at
855–56. On remand, the district court found that the
prosecution had indeed made the secret deal but held that it
was not material to the convictions (or the penalty). See Order
Denying Claim D, Silva v. Woodford, No. 2:90-cv-03311-DT
(C.D. Cal. Dec. 22, 2003), ECF no. 200, at 9–15; see also
Silva v. Brown (“Silva II”), 416 F.3d 980, 984–85 (9th Cir.
2005). In 2005, the same panel of judges of this Court
reversed in part and ordered that the writ be granted as to
Silva’s conviction for the murder of Thorpe, but affirmed the
denial of relief as to the kidnapping, robbery, and firearms
convictions. Silva II, 416 F.3d at 992.

    On November 8, 1991, Shelton filed his first federal
petition alleging that a post-arrest statement was unlawfully
obtained and that the trial court erred by failing to instruct the
jury on diminished capacity. This first petition was denied by
the district court but never considered on the merits by this
Court.7

    Although Silva filed a state habeas petition in 1989 based
on the same underlying facts as the instant Brady claim,
Shelton did not learn of the matter until he discovered, in the
prison law library, this Court’s 2005 opinion granting relief
to Silva. On May 4, 2006, Shelton presented the instant Brady


 6
    Silva’s filed his habeas petition prior to AEDPA’s effective date. Silva
I, 279 F.3d at 831 & n.5.
 7
    On December 16, 1992, Shelton’s first federal petition was denied in
full by the district court. On December 15, 1993, this Court declined to
consider the merits of the petition because Shelton failed to file a Notice
of Appeal with respect to the December 1992 order, although he had filed
a Notice of Appeal with respect to a November 1992 order in which the
district court denied the petition in part and stayed it in part.
                       SHELTON V. MARSHALL                               15

claim to the California Superior Court, which denied relief in
a written decision on August 24, 2006 stating that the secret
agreement did not concern evidence that was “favorable to
petitioner.” The California Court of Appeal summarily denied
relief on November 30, 2006, as did the Supreme Court of
California on June 13, 2007.

    Shelton filed a second federal petition raising his Brady
claim on June 25, 2007. After the district court dismissed the
petition as second and successive, this Court granted
authorization to file a second petition on November 4, 2008
on the ground that the prosecution’s deal with Thomas
constituted newly discovered evidence. Shelton filed his
second petition on December 17, 2008. On April 8, 2013, the
district court denied the petition but granted a certificate of
appealability as to the materiality of the prosecution’s
undisclosed agreement with Thomas. Shelton appeals.

                              II. Analysis

     A. Standard of Review

    Shelton’s habeas petition raising the instant Brady claim
was filed after the effective date of the Antiterrorism and
Effective Death Penalty Act of 1996 (AEDPA). AEDPA
therefore applies to Shelton’s claim, although it was
inapplicable in Silva’s case.8 Under AEDPA, a federal court

 8
   Shelton did not learn of the prosecution’s bargain with Thomas that he
would not submit to mental examination before Shelton’s trial until some
time following this Court’s issuance of its decision in Silva’s case in 2005.
He asks the panel to toll the application of AEDPA based on the State’s
misconduct in failing to advise him of its deal with Thomas even after it
began litigating an essentially identical Brady claim in Silva’s case—as
early as 1989. We do not reach that issue in light of our holding below.
16                    SHELTON V. MARSHALL

may not grant the writ based on a claim adjudicated on the
merits by a state court unless that adjudication “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 . . . 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). The district court’s
denial of the writ is reviewed de novo. Lambert v. Blodgett,
393 F.3d 943, 964 (9th Cir. 2004).

      B. Application of AEDPA

    There are three distinct elements of a Brady violation:
First, “[t]he evidence at issue must be favorable to the
accused, either because it is exculpatory, or because it is
impeaching.” Strickler v. Greene, 527 U.S. 263, 281–82
(1999). Second, “that evidence must have been suppressed by
the State, either willfully or inadvertently.” Id. at 282. Third,
“prejudice must have ensued.” Id.9 The decision of the
California Superior Court was the last reasoned state court
decision in this case and is accordingly the subject of our
review.10 In that decision, the court ruled only on the first
element of Shelton’s claim—whether the suppressed evidence
was favorable to Shelton.



 9
   The terms “prejudice” and “materiality” are used interchangeably. See,
e.g., Silva II, 416 F.3d at 985.
 10
    Where a state court of last resort issues a postcard denial of a habeas
petition, the federal court “looks through” the summary denial and
considers the last reasoned decision by a state court. Ylst v. Nunnemaker,
501 U.S. 797, 803–04 (1991); see also Avila v. Galaza, 297 F.3d 911, 918
(9th Cir. 2002).
                       SHELTON V. MARSHALL                                 17

    The California Superior Court’s denial of Shelton’s
habeas corpus petition on the ground that “it is difficult to
conclude that anything favorable to petitioner was
suppressed” is contrary to clearly established law, as
determined by the Supreme Court. Evidence that the
prosecution believed Thomas to be incompetent was powerful
fodder for impeaching his testimony against Shelton. See
Silva II, 416 F.3d at 987. The State does not dispute that
impeachment evidence, like exculpatory evidence, plainly
constitutes evidence that is favorable to the accused under
Brady’s first prong. See, e.g., United States v. Bagley,
473 U.S. 667, 676 (1985) (“Impeachment evidence . . . as
well as exculpatory evidence, falls within the Brady rule.
Such evidence is ‘evidence favorable to an accused . . . .’”
(citations omitted)).11 We hold that under clearly established
Supreme Court precedent, Shelton satisfies the “evidence
favorable to the accused” element of Brady error. As to the
second element, the State concedes that it made a deal with
Thomas requiring that his competency not be examined prior
to his testimony against Shelton, and that it failed to disclose
the deal to the defense.

    No state court decision has addressed the third element of
Shelton’s Brady claim—whether the suppression of the
impeachment evidence prejudiced him, i.e., was “material.”
The district court applied AEDPA deference in its review of
the materiality of the suppressed evidence because it believed

  11
     See also Banks v. Dretke, 540 U.S. 668, 691 (2004) (“Farr’s paid
informant status, qualifies as evidence advantageous to Banks.”);
Strickler, 527 U.S. at 280 (“We have . . . held that the duty to disclose . . .
encompasses impeachment evidence as well as exculpatory evidence.”
(citation omitted)); Giglio v. United States, 405 U.S. 150, 154 (1972)
(holding “nondisclosure of evidence affecting credibility falls within” the
Brady rule).
18                   SHELTON V. MARSHALL

that the state court meant “material” when it said “favorable.”
We will not read the state court opinion as meaning
something other than what it plainly said. We accordingly
examine the materiality question de novo. See Porter v.
McCollum, 558 U.S. 30, 38–39 (2009); Rompilla v. Beard,
545 U.S. 374, 390 (2005); Wiggins v. Smith, 539 U.S. 510,
534 (2003); see also Amado v. Gonzalez, 758 F.3d 1119,
1131, 1136–38 (9th Cir. 2014).

     C. Materiality

    “[The] touchstone of materiality is a ‘reasonable
probability’ of a different result . . . . The question is not
whether the defendant would more likely than not have
received a different verdict with the evidence, but whether in
its absence he received a fair trial, understood as a trial
resulting in a verdict worthy of confidence.” Kyles v. Whitley,
514 U.S. 419, 434 (1995). The relevant question is whether
“the government’s evidentiary suppression ‘undermines
confidence in the outcome of the trial.’” Id. (quoting Bagley,
473 U.S. at 678). The omitted evidence “must be evaluated in
the context of the entire record.” United States v. Agurs,
427 U.S. 97, 112 (1976).12

    Thomas provided “the glue that held the prosecution’s
case [for the first-degree murder of Thorpe] together.” Horton
v. Mayle, 408 F.3d 570, 579 (9th Cir. 2005). His “testimony
was the only direct evidence establishing that [Shelton] had
a premeditated plan to kill” or that he deliberated—the key
issue with respect to whether he was guilty of first-degree,
rather than second-degree, murder. Gonzalez v. Wong,

  12
     Once prejudice is shown under this standard, further harmless-error
review does not apply. See Kyles, 514 U.S. at 435.
                      SHELTON V. MARSHALL                               19

667 F.3d 965, 986 (9th Cir. 2011).13 The district court
appreciated that there exists a “reasonable probability of a
different result” where, had the suppressed evidence been
disclosed, the defendant might well have been convicted of a
different offense or a different degree of the crime. Kyles, 514
U.S. at 434. That is, a probability of a total acquittal is not
required to establish prejudice.

    We conclude that had Thomas’s testimony against
Shelton been excluded as a result of the prosecution’s secret
efforts to preclude an inquiry into his competency, there is a
reasonable probability that the jury would not have found
Shelton guilty of deliberate and premeditated first-degree
murder—that the outcome of the proceeding would have been
different. Certainly, viewing the record as a whole we cannot
be confident that the verdict would have been the same. We

    13
        The jury was instructed that first-degree murder was either:
(1) “murder which occurs during the commission or attempt to commit the
crime of robbery,” or (2) “murder which is perpetrated by any kind of
willful, deliberate and premeditated killing.” The verdict reflects that the
jury convicted Shelton of the first-degree murder of Thorpe based on the
latter theory and rejected the former.

    Although we hold in a memorandum disposition filed concurrently
with this opinion that the evidence, apart from Thomas’s testimony
regarding Shelton’s intentional participation in the kidnapping of Thorpe
and Craig, precludes a finding of a reasonable probability of a different
outcome on the kidnapping counts, at the time of trial kidnapping was not
a predicate offense for first-degree felony murder. Rather, murder
occurring in the course of a kidnapping was punishable as second-degree
murder only. See Cal. Penal Code § 189 (West 1970 & Supp. 1988). In
1990, Proposition 115 amended section 189 to include kidnapping as a
predicate offense for first-degree felony murder. See Cal. Penal Code
§ 189 (West Supp. 1999) (“Historical and Statutory Notes”); People v.
Davis, 896 P.2d 119, 146 & n.11 (Cal. 1995). The amendment did not
apply retroactively, however. See id.
20                SHELTON V. MARSHALL

do not rely on the possibility that Thomas’s testimony was
excludable, however, as we also hold that there was a
reasonable probability of a different outcome had Thomas’s
testimony been admitted and then impeached by evidence of
the prosecution’s undisclosed deal with him.

       We cannot overemphasize the importance of
       allowing a full and fair cross-examination of
       government witnesses whose testimony is
       important to the outcome of the case. Had the
       full extent of the prosecution’s deal with
       Norman Thomas been disclosed to the
       defense, a full cross-examination of this
       critical witness would have revealed that even
       the prosecution viewed Thomas’s testimony
       with some doubt.

Silva II, 416 F.3d at 986–87 (internal citations and quotation
marks omitted).

    Shelton and Thomas gave very different accounts of
Thorpe’s murder and Shelton’s role in it, with Shelton
asserting that he was surprised and even endangered by
Silva’s actions, while Thomas claimed that Shelton clearly
knew what was about to happen to Thorpe and indeed
actively and eagerly played a part in it. According to Shelton,
(1) he thought that he was taking Thorpe up the hill in order
to conceal him and that Silva went to get more chains; (2) he
did not know that Thorpe would be killed; (3) he was
surprised when Silva opened fire on Thorpe and had to jump
out of harm’s way himself; and (4) he shot at Thorpe only
after Silva had already felled him with forty-five bullets (a
clip and a half) and only because he believed that Silva would
shoot him on the spot if he did not comply with his order. By
                   SHELTON V. MARSHALL                       21

contrast, Thomas testified that (1) Shelton guarded Thorpe
knowing that Silva was going to retrieve a machine gun; (2)
Shelton returned from the hill in order to turn up the
stereo—indicating that he knew in advance that Thorpe
would be shot and tried to conceal the sound; (3) while
waiting for Silva’s return, Shelton told Thorpe to “look at the
mountain, because it was the last thing he would see”; and (4)
Shelton laughed while recounting Thorpe’s murder. Thomas
also described Shelton as taking the gun from Silva in order
to shoot Thorpe, rather than being ordered to do so or risk
being shot himself.

    No other evidence corroborated this account by Thomas
of Shelton deliberating and premeditating the killing of
Thorpe—not Shelton’s statements to investigators, his trial
testimony, the notes he passed to Thomas in jail, or any
physical or forensic evidence. “[I]t was [Thomas’s tainted
testimony alone] that revealed that [Shelton] confessed” to
knowing in advance that Thorpe would be killed and to
participating willingly in his execution, Horton, 408 F.3d at
579—by far the most damning evidence heard by the jury,
see Arizona v. Fulminante, 499 U.S. 279, 296 (1991).

    The materiality of evidence “is best understood by taking
the word of the prosecutor.” Kyles, 514 U.S. at 444; see also
Banks v. Dretke, 540 U.S. 676, 700 (2004); Horton, 408 F.3d
at 579. In his closing argument, DePasquale emphasized the
“look at the mountain” statement, arguing that it
demonstrated that Thorpe never had a chance to survive.
Moreover, in entering the judgment, the trial judge cited “the
transactions . . . of turning up the hi-fi or this loud speaker”
as the basis of the first-degree conviction because it
demonstrated that “Shelton had advance knowledge of the
plan involving Thorpe” and that “the purpose of the mission
22                 SHELTON V. MARSHALL

at the time [was] the execution of Thorpe.” This evidence that
the prosecutor and the district judge found central to the first-
degree conviction came solely from Thomas—a witness
whose testimony even the prosecution seriously doubted and
whom it precluded from obtaining a competency
examination.

    In Silva II, this Court explained why the very deal at issue
in this case, had it not been illegally suppressed, would have
severely undermined the State’s case and created “a
reasonable probability of a different result”:

            Had the prosecution’s deal foreclosing a
        psychiatric examination of Thomas been
        revealed, it could have had a profound effect
        on the jury’s assessment of Thomas’s
        testimony. . . .The fact of the undisclosed deal
        bears critically and directly on Thomas’s
        competence and credibility as a witness. Had
        the defense known that the prosecution had
        required, as a condition of Thomas’s plea
        bargain, that he agree not to be psychiatrically
        evaluated before testifying, competent defense
        counsel would have ensured that the jury was
        made aware of the potentially devastating fact
        that the state itself doubted Thomas’s mental
        competency. . . . [T]he very fact that the
        prosecution had sought to keep evidence of
        Thomas’s mental capacity away from the jury
        might have diminished the State’s own
        credibility as a presenter of evidence.

           In sum, the fact of the prosecution’s
        undisclosed deal with Thomas, had it been
                   SHELTON V. MARSHALL                         23

        presented to the jury, would have put the
        testimony of this critical witness in a
        substantially different light, both directly, by
        casting doubt on the accuracy of Thomas’s
        testimony, and indirectly, by inducing the
        defense to focus the jury’s attention on
        Thomas’s lapses and inconsistencies and by
        calling into question the prosecutor’s faith in
        the competence of his own witness.

Silva II, 416 F.3d at 987–88 (citations and internal quotation
marks omitted).

     The district court nonetheless believed that the suppressed
evidence was not material because of Shelton’s statements
“that he accompanied Silva in walking Thorpe up the hill,
guarded Thorpe in Silva’s absence, . . . jumped behind a tree
to avoid being shot . . . [, and] admitted that he shot Thorpe
with Silva’s machine gun after Silva fired one and a half clips
into the victim.” While these statements provide
corroboration of Shelton’s participation in Thorpe’s murder
such that even a jury informed of the deal with Thomas might
well have found Shelton guilty of second-degree
murder—that is, murder in the course of a kidnapping—they
are fully consistent with and simply form a part of Shelton’s
explanation that he was not aware in advance of what was
about to happen to Thorpe and thought that he was helping
move him to a location out of the public view. Thus, the
statements viewed in context provide little if any evidence as
to the premeditation or deliberation required for a first-degree
conviction. See supra note 13. Indeed, Shelton’s testimony
that he had to jump out of the line of fire, if credited, would
be evidence that he was surprised by Silva’s conduct, and the
fact that Shelton told the investigators that, in fear for his own
24                 SHELTON V. MARSHALL

life, he fired at Thorpe after Silva had already shot him forty-
five times does not indicate premeditation and deliberation.
Had defense counsel been able to cross-examine Thomas
thoroughly about the deal’s requirement that he not receive a
psychiatric examination before testifying and explain to the
jury that even the prosecution was concerned about his
mental stability, if not his sanity, there is a reasonable
probability that the jury would not have reached the verdict
it did. Certainly, as Thomas’s evidence was the primary
evidence upon which the prosecution relied to establish
premeditation and deliberation, we cannot say with
confidence that had his testimony been impeached on the
ground of his potential mental incapacity or insanity and the
prosecution’s unlawful deal to keep that information from the
jury, the jury would have nevertheless returned a verdict of
first-degree rather than second-degree murder.

    True, Shelton’s admissions that he was present for
Thorpe’s killing, watched Thorpe while waiting for Silva, and
shot at his body after Silva already had fired forty-five rounds
into him, if taken in isolation, could constitute circumstantial
evidence that he knew in advance that Thorpe would be
killed. Nevertheless, we have held that prejudice is
established where the concealed evidence would impeach the
only witness to provide direct evidence of the defendant’s
mens rea. See Hayes v. Brown, 399 F.3d 972, 985 (9th Cir.
2005) (en banc) (finding suppressed evidence material where
tainted witness’s testimony “was the centerpiece of the
prosecution’s case” and “[n]early all of the other evidence
against Hayes was circumstantial.”); see also Gonzalez,
667 F.3d at 986; Horton, 408 F.3d at 580; Benn v. Lambert,
283 F.3d 1040, 1062 (9th Cir. 2002). We repeat: Thomas’s
testimony supplied the only direct evidence that Shelton
deliberated and premeditated Thorpe’s murder, as opposed to
                  SHELTON V. MARSHALL                       25

acting on Silva’s command and in fear for his life. Moreover,
this Court has previously held the suppression of the
prosecution’s deal with Thomas to be prejudicial in Silva’s
case, notwithstanding physical evidence of the crime
corroborating Thomas’s story, fingerprint analysis placing
Silva at the scene, and Silva’s equivocating statements to the
police post-arrest. See Silva II, 416 F.3d at 984. See also
Order Denying Claim D, Silva v. Woodford, No. 2:90-cv-
03311-DT (C.D. Cal. Dec. 22, 2003), ECF no. 200, at 9–15.
There is similarly a reasonable probability that the jury would
have in this case reached a different verdict had Thomas been
thoroughly impeached, notwithstanding the fact that Shelton
admitted being present for Thorpe’s murder after having
initially denied as much. In short, we reiterate, the
suppression by the prosecution of its agreement with Thomas
that he not obtain a mental examination prior to his testimony
undermines confidence in the verdict.

    The State argues that a statement that Shelton made to an
investigator on February 1 demonstrates the veracity of
Thomas’s account of Thorpe’s murder and rendered his
testimony superfluous. According to an investigator’s
testimony, while Shelton was denying his presence at
Thorpe’s murder in that interview, he claimed that he was in
the cabin at the time and that Thomas told him to turn up the
stereo. At trial DePasquale argued that this made it “almost
obvious that [Shelton is] putting Thomas in his position and
what he’s saying there is in essence an admission that he was
trying to lay at Thomas’ feet an admission that he went in
there and he said turn up that stereo.”

    This disputed statement about the stereo is not, however,
sufficient to give us confidence in the first-degree verdict.
The case is riddled with inconsistencies regarding who did
26                    SHELTON V. MARSHALL

what. Indeed, at one point, Thomas told the prosecution “that
he was with Silva when Thorpe was killed.” Silva II, 416 F.3d
at 988 (emphasis added). Moreover, the investigator who
testified to Shelton’s statement about the stereo also testified
that he “[didn’t] remember exactly what [Shelton] told
[him].”14

     A comparison of the evidence against Shelton with
respect to Craig’s murder strongly supports our conclusion
that he was prejudiced by the State’s Brady violation. The
jury heard evidence of premeditation and deliberation with
respect to Craig’s murder—Shelton’s admission to the
investigators that the men had discussed kidnapping and
killing a girl prior to the crimes—yet it returned a verdict of
only second-degree murder with respect to Shelton’s role in
her killing. The State concedes that this was because of the
jury’s “finding that there was insufficient evidence of
deliberation or premeditation in killing Craig.” Meanwhile,
the only direct evidence that Shelton deliberated or
premeditated the killing of Thorpe came from a witness
whose vulnerability to charges of incompetency or insanity
the State felt compelled to conceal. The other evidence that
pertained to premeditation and deliberation applied equally,
if not more strongly, to the murder of Craig as to that of
Thorpe. It follows that if the jury had known about the
prosecution’s secret deal with Thomas, there is an even
stronger probability than in Craig’s case that it would have
returned a verdict other than first-degree murder—that it


  14
     At trial, Shelton maintained that the conversation about the stereo
volume occurred several hours before Thorpe was taken up the hill and
was unconnected to the killing, that he never said otherwise, and that the
investigator either intentionally lied about what Shelton said regarding the
stereo in the interview or mistakenly recounted an interview with Thomas.
                      SHELTON V. MARSHALL                             27

would have found insufficient evidence to conclude beyond
a reasonable doubt that Shelton premeditated and deliberated
as to Thorpe’s killing.15

     We reject the State’s contention that evidence of the
prosecution’s secret deal with Thomas would have been
cumulative to the impeachment evidence presented to the
jury. Thomas’s accident and the fact that the prosecution had
dropped murder charges against him in exchange for his
cooperation were mentioned briefly during the trial.
However, “the undisclosed evidence was not duplicative of
the impeachment evidence actually presented, but rather was
of a different kind. It ‘would have provided the defense with
a new and different ground of impeachment.’” Silva II,
416 F.3d at 989 (quoting Benn, 283 F.3d at 1056). Evidence
that murder charges had been dropped “could cast doubt only
on Thomas’s forthrightness, not his competence to testify,”
id. at 989, and the defense’s argument that Thomas “does not
have a good memory” was far less compelling than the
suppressed evidence that the prosecution doubted his mental
stability to the degree that it stopped him from being
psychiatrically examined.

   Finally, “[t]he prosecutor’s own conduct in keeping the
deal secret underscores the deal’s importance.” Silva II,
416 F.3d at 990. His “actions . . . speak as loud as his
words. . . . The State’s deliberate and strategic decision to


  15
      Moreover, if the implausibility of Shelton’s claims that Craig was
there voluntarily, even after her boyfriend had been killed, did not
persuade the jury to find him unworthy of belief and to reject his account
of being surprised by her murder, there is no reason to think that the
inconsistencies in his statements would have caused it to reach a verdict
of first-degree murder with respect to Thorpe, either.
28                     SHELTON V. MARSHALL

make the deal and not to disclose it suggests the weakness of
its post hoc claims that the evidence was irrelevant.” Id. If
Thomas’s testimony was unnecessary to Shelton’s conviction
as the State now claims, then there was no reason for it to
take furtive actions to ensure that the jury never heard that
both it and Thomas’s lawyer believed that he might well be
incompetent or insane. Indeed, the deal was premised on
DePasquale’s agreement with Gay that credible testimony by
Thomas was necessary to obtaining a conviction of both
Shelton and Silva.

                           III. Conclusion

    In sum, the prosecution committed Brady error by
concealing from the defense and the jury its deal precluding
an examination of the mental competency of its star witness.
We find this error prejudicial with respect to Shelton’s first-
degree murder conviction in part because Thomas was the
only witness who provided direct evidence that Shelton
deliberated and premeditated the murder of Thorpe, and in
part because it is the prosecution’s suppression of the
powerful impeachment evidence that “‘undermines
confidence in the outcome of the trial.’” Kyles, 514 U.S. at
434 (quoting Bagley, 473 U.S. at 678). Although we have
serious doubts about the good-faith of the prosecution as a
whole and find DePasquale’s misconduct inexcusable, the
extremely strong evidence in the record, aside from Thomas’s
testimony, regarding Shelton’s commission of the other
crimes precludes us from granting relief with respect to those
convictions.16 We leave those charges, which we address in
the memorandum disposition filed concurrently with this
opinion, undisturbed. The district court is directed to issue the

 16
      Shelton does not challenge his convictions for weapons offenses.
                 SHELTON V. MARSHALL                   29

writ ordering the State to retry Shelton for the murder of
Thorpe within a reasonable time or to resentence him based
on the remaining convictions.

  REVERSED IN PART, AFFIRMED IN PART, AND
REMANDED FOR ISSUANCE OF A WRIT.
