(Slip Opinion)              OCTOBER TERM, 2016                                       1

                                       Syllabus

         NOTE: Where it is feasible, a syllabus (headnote) will be released, as is
       being done in connection with this case, at the time the opinion is issued.
       The syllabus constitutes no part of the opinion of the Court but has been
       prepared by the Reporter of Decisions for the convenience of the reader.
       See United States v. Detroit Timber & Lumber Co., 200 U. S. 321, 337.


SUPREME COURT OF THE UNITED STATES

                                       Syllabus

                 TURNER ET AL. v. UNITED STATES

     CERTIORARI TO THE DISTRICT OF COLUMBIA COURT OF 

                         APPEALS 


    No. 15–1503. Argued March 29, 2017—Decided June 22, 2017*

Petitioners—Timothy Catlett, Russell Overton, Levy Rouse, Kelvin
  Smith, Charles and Christopher Turner, and Clifton Yarborough—
  and several others were indicted for the kidnaping, robbery, and
  murder of Catherine Fuller. At trial, the Government advanced the
  theory that Fuller was attacked by a large group of individuals. Its
  evidentiary centerpiece consisted of the testimony of Calvin Alston
  and Harry Bennett, who confessed to participating in a group attack
  and cooperated with the Government in return for leniency. Several
  other Government witnesses corroborated aspects of Alston’s and
  Bennett’s testimony. Melvin Montgomery testified that he was in a
  park among a group of people, heard someone say they were “going to
  get that one,” saw petitioner Overton pointing to Fuller, and saw sev-
  eral persons, including some petitioners, cross the street in her direc-
  tion. Maurice Thomas testified that he saw the attack, identified
  some petitioners as participants, and later overheard petitioner Cat-
  lett say that they “had to kill her.” Carrie Eleby and Linda Jacobs
  testified that they heard screams coming from an alley where a “gang
  of boys” was beating someone near a garage, approached the group,
  and saw some petitioners participating in the attack. Finally, the
  Government played a videotape of petitioner Yarborough’s statement
  to detectives, describing how he was part of a large group that carried
  out the attack. None of the defendants rebutted the prosecution wit-
  nesses’ claims that Fuller was killed in a group attack. The seven pe-
  titioners were convicted.
     Long after their convictions became final, petitioners discovered
——————
  *Together with No. 15–1504, Overton v. United States, also on certio-
rari to the same court.
2                     TURNER v. UNITED STATES

                                 Syllabus

    that the Government had withheld evidence from the defense at the
    time of trial. In postconviction proceedings, they argued that seven
    specific pieces of withheld evidence were both favorable to the de-
    fense and material to their guilt under Brady v. Maryland, 373 U. S.
    83. This evidence included the identity of a man seen running into
    the alley after the murder and stopping near the garage where
    Fuller’s body had already been found; the statement of a passerby
    who claimed to hear groans coming from a closed garage; and evi-
    dence tending to impeach witnesses Eleby, Jacobs, and Thomas. The
    D. C. Superior Court rejected petitioners’ Brady claims, finding that
    the withheld evidence was not material. The D. C. Court of Appeals
    affirmed.
Held: The withheld evidence is not material under Brady. Pp. 9–14.
    (a) The Government does not contest petitioners’ claim that the
 withheld evidence was “favorable to the defense.” Petitioners and the
 Government, however, do contest the materiality of the undisclosed
 Brady information. Such “evidence is ‘material’ . . . when there is a
 reasonable probability that, had the evidence been disclosed, the re-
 sult of the proceeding would have been different.” Cone v. Bell, 556
 U. S. 449, 469–470. “A ‘reasonable probability’ of a different result”
 is one in which the suppressed evidence “ ‘undermines confidence in
 the outcome of the trial.’ ” Kyles v. Whitley, 514 U. S. 419, 434. To
 make that determination, this Court “evaluate[s]” the withheld evi-
 dence “in the context of the entire record.” United States v. Agurs,
 427 U. S. 97, 112. Pp. 9–11.
    (b) Petitioners’ main argument is that, had they known about the
 withheld evidence, they could have challenged the Government’s
 basic group attack theory by raising an alternative theory, namely,
 that a single perpetrator (or two at most) had attacked Fuller. Con-
 sidering the withheld evidence “in the context of the entire record,”
 Agurs, supra, at 112, that evidence is too little, too weak, or too dis-
 tant from the main evidentiary points to meet Brady’s standards.
    A group attack was the very cornerstone of the Government’s case,
 and virtually every witness to the crime agreed that Fuller was killed
 by a large group of perpetrators. It is not reasonably probable that
 the withheld evidence could have led to a different result at trial. Pe-
 titioners’ problem is that their current alternative theory would have
 had to persuade the jury that both Alston and Bennett falsely con-
 fessed to being active participants in a group attack that never oc-
 curred; that Yarborough falsely implicated himself in that group at-
 tack and yet gave a highly similar account of how it occurred; that
 Thomas, an otherwise disinterested witness, wholly fabricated his
 story; that both Eleby and Jacobs likewise testified to witnessing a
 group attack that did not occur; and that Montgomery in fact did not
                     Cite as: 582 U. S. ____ (2017)                    3

                                Syllabus

  see petitioners and others, as a group, identify Fuller as a target and
  leave together to rob her.
    As for the undisclosed impeachment evidence, the record shows
  that it was largely cumulative of impeachment evidence petitioners
  already had and used at trial. This is not to suggest that impeach-
  ment evidence is immaterial with respect to a witness who has al-
  ready been impeached with other evidence, see Wearry v. Cain, 577
  U. S. ___, ___–___. But in the context of this trial, with respect to
  these witnesses, the cumulative effect of the withheld evidence is in-
  sufficient to undermine confidence in the jury’s verdict, see Smith v.
  Cain, 565 U. S. 73, 75–76. Pp. 11–14.
116 A. 3d 894, affirmed.

  BREYER, J., delivered the opinion of the Court, in which ROBERTS,
C. J., and KENNEDY, THOMAS, ALITO, and SOTOMAYOR, JJ., joined. KA-
GAN, J., filed a dissenting opinion, in which GINSBURG, J., joined. GOR-
SUCH, J., took no part in the consideration or decision of the cases.
                        Cite as: 582 U. S. ____ (2017)                              1

                             Opinion of the Court

     NOTICE: This opinion is subject to formal revision before publication in the
     preliminary print of the United States Reports. Readers are requested to
     notify the Reporter of Decisions, Supreme Court of the United States, Wash-
     ington, D. C. 20543, of any typographical or other formal errors, in order
     that corrections may be made before the preliminary print goes to press.


SUPREME COURT OF THE UNITED STATES
                                   _________________

                         Nos. 15–1503 and 15–1504
                                   _________________


     CHARLES S. TURNER, ET AL., PETITIONERS
15–1503               v.
                UNITED STATES

           RUSSELL L. OVERTON, PETITIONER
15–1504                   v.
                   UNITED STATES
 ON WRITS OF CERTIORARI TO THE DISTRICT OF COLUMBIA 

                  COURT OF APPEALS

                                 [June 22, 2017] 


  JUSTICE BREYER delivered the opinion of the Court.
  In Brady v. Maryland, 373 U. S. 83 (1963), this Court
held that the government violates the Constitution’s Due
Process Clause “if it withholds evidence that is favorable
to the defense and material to the defendant’s guilt or
punishment.” Smith v. Cain, 565 U. S. 73, 75 (2012)
(emphasis added) (summarizing Brady holding). In 1985
the seven petitioners in these cases were tried together in
the Superior Court for the District of Columbia for the
kidnaping, armed robbery, and murder of Catherine
Fuller. Long after petitioners’ convictions became final, it
emerged that the Government possessed certain evidence
that it failed to disclose to the defense. The only question
before us here is whether that withheld evidence was
“material” under Brady. The D. C. Superior Court, after a
16-day evidentiary hearing, determined that the withheld
2                TURNER v. UNITED STATES

                     Opinion of the Court

evidence was not material. Catlett v. United States, Crim.
No. 8617–FEL–84 etc. (Aug. 6, 2012), App. to Pet. for Cert.
in No. 15–1503, pp. 84a, n. 4, 81a–131a. The D. C. Court
of Appeals reviewed the record, reached the same conclu-
sion, and affirmed the Superior Court. 116 A. 3d 894
(2015). After reviewing the record, we reach the same
conclusion as did the lower courts.
                              I
  In these fact-intensive cases, we set out here only a
basic description of the record facts along with our reasons
for reaching our conclusion. We refer those who wish
more detail to the opinions of the lower courts. App. to
Pet. for Cert. in No. 15–1503, at 81a–131a; 116 A. 3d 894.
                            A
                         The Trial
  On March 22, 1985, a grand jury indicted the seven
petitioners—Timothy Catlett, Russell Overton, Levy
Rouse, Kelvin Smith, Charles Turner, Christopher Turner,
and Clifton Yarborough—and several others for the kid-
naping, robbery, and murder of Catherine Fuller. The
evidence produced at their joint trial showed that on
October 1, 1984, at around 4:30 p.m., Catherine Fuller left
her home to go shopping. At around 6 p.m., William
Freeman, a street vendor, found Fuller’s body inside an
alley garage between Eighth and Ninth Street N. E., just a
few blocks from Fuller’s home. See Appendix, infra (show-
ing a map of the area in which the murder was commit-
ted). Fuller had been robbed, severely beaten, and sodo-
mized with an object that caused extensive internal
injuries.
  The Government advanced the theory at trial that
Fuller had been attacked in the alley by a large group of
individuals, including petitioners; codefendants Steve
Webb, Alfonso Harris, and Felicia Ruffin; as well as by
                 Cite as: 582 U. S. ____ (2017)            3

                     Opinion of the Court

Calvin Alston and Harry Bennett. The Government’s
evidentiary centerpiece consisted of testimony by Alston
and Bennett, who confessed to participating in the offense
and who cooperated with the Government in return for
leniency. Although the testimony of Alston and Bennett
diverged on minor details, it was consistent in stating
that, and describing how, Fuller was attacked by a siz-
able group of individuals, including petitioners and they
themselves.
  Alston testified that at about 4:10 p.m. on the day of the
murder, he arrived in a park located on H Street between
Eighth and Ninth Streets. He said he found a group of
people gathered there. It included petitioners Levy Rouse,
Russell Overton, Christopher Turner, Charles Turner,
Kelvin Smith, Clifton Yarborough, and Timothy Catlett,
as well as several codefendants and others. Those in the
group were talking and singing while Catlett was banging
out a beat. Alston suggested “getting paid” by robbing
someone. App. A467. Catlett, Overton, Rouse, Smith,
Charles Turner, Christopher Turner, Yarborough, and
several others agreed. Alston pointed at Catherine Fuller,
who was walking on the other side of H Street near the
corner of H and Eighth Streets. Those in the group said
they were “game for getting paid.” Id., at A471–A472.
Alston, Rouse, Yarborough, and Charles Turner crossed H
Street moving toward Eighth Street and followed Fuller
down Eighth Street. The rest of the group crossed H
Street and moved toward Ninth Street. When Alston’s
group approached Fuller, Charles Turner shoved her into
an alley that runs between Eighth and Ninth Streets.
Charles Turner, Rouse, and Alston began punching Fuller.
They were soon joined by Christopher Turner, Smith, and
others. All of them continued to hit and kick Fuller until
she fell to the ground. Rouse and Charles Turner then
carried Fuller to the center of the alley and dropped her in
front of a garage located at the point where the alley joins
4               TURNER v. UNITED STATES

                     Opinion of the Court

another, perpendicular alley that runs toward I Street.
Someone dragged Fuller into the garage. Alston, Rouse,
Charles Turner, Overton, Yarborough, and Catlett fol-
lowed. Others stood outside. Members of the group tore
Fuller’s clothes off and struggled over her change purse.
Overton and Charles Turner then held Fuller’s legs, and
Alston, Catlett, Harris, and Yarborough stood around her
while Rouse sodomized her with a foot-long pipe. Shortly
after, the group dispersed and left the alley.
  Harry Bennett’s testimony was similar. Bennett also
described a group attack. He said that he had gone to the
H Street park, where he saw Rouse, Overton, Christopher
Turner, Smith, Catlett, and others gathered. Alston was
talking to the group about “[g]etting paid” and said “let’s
go get that lady.” Id., at A368–A370. At that point Alston,
Rouse, Overton, and Webb crossed H Street and ap-
proached Fuller, while Catlett, Christopher Turner,
Charles Turner, and Harris followed in a separate group.
Bennett added that he himself went to the corner of
Eighth and H Streets to watch for police. He then went
into the alley and joined the group in kicking and beating
Fuller. He testified that at least 12 people were there,
with some beating Fuller and others watching or picking
up her jewelry. Overton then dragged Fuller into the
garage, and Bennett, Rouse, Christopher Turner, Charles
Turner, Catlett, Smith, Harris, and Webb followed, as did
some “girls.” Id., at A402–A405. Alston and Steve Webb
held Fuller’s legs, and Rouse sodomized her with a pole.
The group then dispersed from the garage and alley.
  The Government presented several other witnesses who
corroborated aspects of Alston’s and Bennett’s testimony,
including the fact that Fuller was attacked by a group.
Melvin Montgomery testified that he was in the H Street
park on the afternoon of the murder. He saw Overton,
Catlett, Rouse, Charles Turner, and others gathered there.
The group was being noisy and singing a song about need-
                 Cite as: 582 U. S. ____ (2017)          5

                     Opinion of the Court

ing money. Somebody then said they were “going to get
that one,” and Montgomery saw that Overton was pointing
to a woman standing on the corner of Eighth Street. Id.,
at 77–79. Overton, Catlett, Rouse, Charles Turner, and
others crossed H Street. Some headed toward Eighth
Street while others went toward Ninth Street. Montgom-
ery did not follow them.
  Maurice Thomas, then 14 years old, testified that he
witnessed the attack itself. Thomas lived in the neighbor-
hood and knew many of the defendants. As he was walk-
ing home, he glanced down the Eighth Street alley and
saw a group surrounding Fuller. Thomas saw Catlett pat
Fuller down and then hit her. He then saw everyone in
the group join in hitting her. Thomas said he knew Cat-
lett, Yarborough, Rouse, Charles Turner, Christopher
Turner, and Smith and recognized them in the group.
Thomas heard Fuller calling for help. He ran home where
he found his aunt, who told him not to tell anyone what he
saw. Later that day, Thomas saw Catlett at a corner
store, and heard Catlett say to someone that they “had to
kill her” because “she spotted someone he was with.” Id.,
at 127–128.
  On the afternoon of the murder, Carrie Eleby and Linda
Jacobs were looking for petitioner Smith, who was Eleby’s
boyfriend, near the corner of H and Eighth Streets. They
heard screams coming from where a “gang of boys” was
beating somebody near the garage in the alley. Id., at
A539–A541. Eleby and Jacobs approached the group.
Eleby recognized Christopher Turner, Smith, Catlett,
Rouse, Overton, Alston, and Webb kicking Fuller while
Yarborough stood nearby. Both Eleby and Jacobs testified
that they saw Rouse sodomize Fuller with a pole. Eleby
added that Overton held Fuller’s legs.
  Finally, the Government played a videotape of a recorded
statement that Yarborough, one of the petitioners, had
given to detectives on December 9, 1984, approximately
6                TURNER v. UNITED STATES

                      Opinion of the Court

two months after the murder. Names were redacted. The
video shows Yarborough describing in detail how he was
part of a large group that forced Fuller into the alley,
jointly robbed and assaulted her, and dragged her into the
garage.
   None of the defendants testified, nor did any of them
try, through witnesses or other evidence, to rebut the
prosecution witnesses’ claim that Fuller was killed in a
group attack. Rather, each petitioner pursued what was
essentially a “not me, maybe them” defense, namely, that
he was not part of the group that attacked Fuller. Each
tried to establish this defense by impeaching witnesses
who had placed that particular petitioner at the scene.
Some, for example, provided evidence that Eleby and
Jacobs had used PCP the day of Fuller’s murder. Some
also tried to establish alibis for the time of Fuller’s death.
   The jury convicted all seven petitioners, along with
codefendant Steve Webb (who subsequently died). The
jury acquitted codefendants Alfonso Harris and Felicia
Ruffin. On direct appeal, the D. C. Court of Appeals af-
firmed petitioners’ convictions, though it remanded for
resentencing. 545 A. 2d 1202, 1219 (1988). The trial court
resentenced petitioners to the same amount of prison time.
App. to Pet. for Cert. in No. 15–1503, at 82a, n. 2.
                             B
                     The Brady Claims
   Beginning in 2010, petitioners pursued postconviction
proceedings in which they sought to vacate their convic-
tions or to be granted a new trial. App. to Pet. for Cert. in
No. 15–1503, at 84a, n. 4. After petitioners’ convictions
became final, it emerged that the Government possessed
certain evidence that it had withheld from the defense at
the time of trial. Petitioners discovered other withheld
evidence in their review of the trial prosecutor’s case file,
which the Government turned over to petitioners in the
                 Cite as: 582 U. S. ____ (2017)           7

                     Opinion of the Court

course of the postconviction proceedings. Among other
postconviction claims, petitioners contended that the
withheld evidence was both favorable and material, enti-
tling them to relief under Brady.
   The D. C. Superior Court considered petitioners’ Brady
claims as part of a 16-day evidentiary hearing. It rejected
those claims, finding that “none of the undisclosed infor-
mation was material.” App. to Pet. for Cert. in No. 15–
1503, at 130a. The D. C. Court of Appeals affirmed. 116
A. 3d, at 901. It similarly concluded that the withheld
evidence was not material under Brady. 116 A. 3d, at
913–926. At issue in those proceedings were the following
seven specific pieces of evidence:
   1. The identity of James McMillan. Freeman, the ven-
dor who discovered Fuller’s body in the alley garage,
testified at trial that, while he was waiting for police to
arrive, he saw two men run into the alley and stop near
the garage for about five minutes before running away
when an officer approached. One of the men had a bulge
under his coat. Early in the trial, codefendant Harris’
counsel had requested the identity of the two men to
confirm that her client was not one of them. But the
Government refused to disclose the men’s identity.
   In their postconviction review of the prosecutor’s files,
petitioners learned that Freeman had identified the two
men he saw in the alley as James McMillan and Gerald
Merkerson. McMillan lived in a house which opens in the
back onto a connecting alley. In the weeks following
Fuller’s murder, but before petitioners’ trial, McMillan
was arrested for beating and robbing two women in the
neighborhood. Neither attack included a sexual assault.
Separately, petitioners learned that seven years after
petitioners’ trial, McMillan had robbed, sodomized, and
murdered a young woman in an alley.
   2. The interview with Willie Luchie. The prosecutor’s
notes also recorded an undisclosed interview with Willie
8                TURNER v. UNITED STATES

                     Opinion of the Court

Luchie, who told the prosecutor that he and three others
walked through the alley on their way to an H Street
liquor store between 5:30 and 5:45 p.m. on the evening of
the murder. As the group walked by the garage, Luchie
“heard several groans” and “remembers the doors to the
garage being closed.” App. 25. Another person in the
group recalled “hear[ing] some moans,” while the other
two persons did not recall hearing anything unusual. Id.,
at 27, 53; id., at A992. The group continued walking
without looking into the garage or otherwise investigating
the source of the sounds. They did not see McMillan or
any other person in the alley when they passed through.
   3. The interviews with Ammie Davis. Undisclosed notes
written by a police officer and the prosecutor refer to two
interviews with Ammie Davis, who had been arrested for
disorderly conduct a few weeks after Fuller’s murder.
Davis initially told a police investigator that she had seen
another individual, James Blue, beat Fuller to death in
the alley. Shortly thereafter, she said she only saw Blue
grab Fuller and push her into the alley. Davis also said
that a girlfriend, whom she did not name, accompanied
her. She promised to call the investigator with more
details, but she did not do so.
   About 9 months later (after petitioners were indicted
but approximately 11 weeks before their trial), a prosecu-
tor learned of the investigator’s notes and interviewed
Davis. The prosecutor’s notes state that Davis did not
provide any more details, except to say that the girlfriend
who accompanied her was nicknamed “ ‘Shorty.’ ” Id., at
267–268. About two months later, which was shortly
before petitioners’ trial, Blue murdered Davis in an unre-
lated drug dispute.
   During the postconviction evidentiary hearing, the
prosecutor who interviewed Davis testified that he did not
disclose Davis’ statement because she acted “playful” and
“not serious” during the interview and he found her to be
                 Cite as: 582 U. S. ____ (2017)           9

                     Opinion of the Court

“totally incredible.” Id., at 269–272. Additionally, the
prosecutor stated that he knew Davis had previously
falsely accused Blue of a different murder, and on another
occasion had falsely accused a different individual of a
different murder.
  4. Impeachment of Kaye Porter and Carrie Eleby. Kaye
Porter accompanied Eleby during an initial interview with
homicide detectives. Porter agreed with Eleby that she
had also heard Alston state that he was involved in rob-
bing Fuller. An undisclosed prosecutorial note states that
in a later interview with detectives, Porter stated that she
did not actually recall hearing Alston’s statement and just
went along with what Eleby said. The note also states
that Eleby likewise admitted that she had lied about
Porter being present during Alston’s statement and had
asked Porter to support her.
  5. Impeachment of Carrie Eleby. A prosecutor’s un-
disclosed note revealed that Eleby said she had been
high on PCP during a January 9, 1985, meeting with
investigators.
  6. Impeachment of Linda Jacobs. An undisclosed note of
an interview with Linda Jacobs said that the detective had
“question[ed] her hard,” and that she had “vacillated”
about what she saw. Id., at A1009. The prosecutor re-
called that the detective “kept raising his voice” and was
“smacking his hand on the desk” during the interview.
Id., at A2298–A2299.
  7. Impeachment of Maurice Thomas. An undisclosed
note of an interview with Maurice Thomas’ aunt stated
that she “does not recall Maurice ever telling her anything
such as this.” Id., at A1010; see id., at 295–296.
                           II
                           A
  The Government does not contest petitioners’ claim
that the withheld evidence was “favorable to the accused,
10                TURNER v. UNITED STATES

                      Opinion of the Court

either because it is exculpatory, or because it is impeach-
ing.” Strickler v. Greene, 527 U. S. 263, 281–282 (1999).
Neither does the Government contest petitioners’ claim
that it “suppressed” the evidence, “either willfully or
inadvertently.” Id., at 282. It does, as it must, concede
that the Brady rule’s “ ‘overriding concern [is] with the
justice of the finding of guilt,’ ” United States v. Bagley,
473 U. S. 667, 678 (1985) (quoting United States v. Agurs,
427 U. S. 97, 112 (1976)), and that the Government’s
“ ‘interest . . . in a criminal prosecution is not that it shall
win a case, but that justice shall be done,’ ” Kyles v. Whit-
ley, 514 U. S. 419, 439 (1995) (quoting Berger v. United
States, 295 U. S. 78, 88 (1935)). Consistent with these
principles, the Government assured the Court at oral
argument that subsequent to petitioners’ trial, it has
adopted a “generous policy of discovery” in criminal cases
under which it discloses any “information that a defendant
might wish to use.” Tr. of Oral Arg. 47–48. As we have
recognized, and as the Government agrees, ibid., “[t]his is
as it should be.” Kyles, supra, at 439 (explaining that a
“ ‘prudent prosecutor[’s]’ ” better course is to take care to
disclose any evidence favorable to the defendant (quoting
Agurs, supra, at 108)).
    Petitioners and the Government, however, do contest
the materiality of the undisclosed Brady information.
“[E]vidence is ‘material’ within the meaning of Brady
when there is a reasonable probability that, had the evi-
dence been disclosed, the result of the proceeding would
have been different.” Cone v. Bell, 556 U. S. 449, 469–470
(2009) (citing Bagley, supra, at 682). “A ‘reasonable prob-
ability’ of a different result” is one in which the suppressed
evidence “ ‘undermines confidence in the outcome of the
trial.’ ” Kyles, supra, at 434 (quoting Bagley, supra, at
678). In other words, petitioners here are entitled to a
new trial only if they “establis[h] the prejudice necessary
to satisfy the ‘materiality’ inquiry.” Strickler, supra, at
                 Cite as: 582 U. S. ____ (2017)          11

                     Opinion of the Court

282.
  Consequently, the issue before us here is legally simple
but factually complex. We must examine the trial record,
“evaluat[e]” the withheld evidence “in the context of the
entire record,” Agurs, supra, at 112, and determine in light
of that examination whether “there is a reasonable prob-
ability that, had the evidence been disclosed, the result of
the proceeding would have been different.” Cone, supra,
at 470 (citing Bagley, supra, at 682). Having done so, we
agree with the lower courts that there was no such rea-
sonable probability.
                             B
  Petitioners’ main argument is that, had they known
about McMillan’s identity and Luchie’s statement, they
could have challenged the Government’s basic theory that
Fuller was killed in a group attack. Petitioners contend
that they could have raised an alternative theory, namely,
that a single perpetrator (or two at most) had attacked
Fuller. According to petitioners, the groans that Luchie
and his companion heard when they walked through the
alley between 5:30 and 5:45 p.m. suggest that the attack
was taking place inside the garage at that moment. The
added facts that the garage was small and that Luchie’s
group saw no one in the alley could bolster a “single at-
tacker” theory. Freeman’s recollection that one garage
door was open when he found Fuller’s body at around 6
p.m., combined with Luchie’s recollection that both doors
were shut around 5:30 or 5:45 p.m., could suggest that one
or two perpetrators were in the garage when Luchie
walked by but left before Freeman arrived. McMillan’s
identity as one of the men Freeman saw enter the alley
after Freeman discovered Fuller’s body would have re-
vealed McMillan’s criminal convictions in the months
before petitioners’ trial. Petitioners argue that together,
this evidence would have permitted the defense to knit
12               TURNER v. UNITED STATES

                     Opinion of the Court

together a theory that the group attack did not occur at
all—and that it was actually McMillan, alone or with an
accomplice, who murdered Fuller. They add that they
could have used the investigators’ failure to follow up on
Ammie Davis’ claim about James Blue, and the various
pieces of withheld impeachment evidence, to suggest that
an incomplete investigation had ended up accusing the
wrong persons.
   Considering the withheld evidence “in the context of the
entire record,” however, Agurs, supra, at 112, we conclude
that it is too little, too weak, or too distant from the main
evidentiary points to meet Brady’s standards. As petition-
ers recognize, McMillan’s guilt (or that of any other single,
or near single, perpetrator) is inconsistent with petition-
ers’ guilt only if there was no group attack. But a group
attack was the very cornerstone of the Government’s case.
The witnesses may have differed on minor details, but
virtually every witness to the crime itself agreed as to a
main theme: that Fuller was killed by a large group of
perpetrators. The evidence at trial was such that, even
though petitioners knew that Freeman saw two men enter
the alley after he discovered Fuller’s body, that one ap-
peared to have a bulky object hidden under his coat, and
that both ran when the police arrived, none of the peti-
tioners attempted to mount a defense that implicated
those men as alternative perpetrators acting alone.
   Is it reasonably probable that adding McMillan’s identity,
and Luchie’s ambiguous statement that he heard groans
but saw no one, could have led to a different result at
trial? We conclude that it is not. The problem for peti-
tioners is that their current alternative theory would have
had to persuade the jury that both Alston and Bennett
falsely confessed to being active participants in a group
attack that never occurred; that Yarborough falsely impli-
cated himself in that group attack and, through coordinated
effort or coincidence, gave a highly similar account of
                 Cite as: 582 U. S. ____ (2017)           13

                     Opinion of the Court

how it occurred; that Thomas, a disinterested witness who
recognized petitioners when he happened upon the attack
and heard Catlett refer to it later that night, wholly fabri-
cated his story; that both Eleby and Jacobs likewise testi-
fied to witnessing a group attack that did not occur; and
that Montgomery in fact did not see petitioners and oth-
ers, as a group, identify Fuller as a target and leave the
park to rob her.
   With respect to the undisclosed impeachment evidence,
the record shows that it was largely cumulative of im-
peachment evidence petitioners already had and used at
trial. For example, the jury heard multiple times about
Eleby’s frequent PCP use, including Eleby’s own testimony
that she and Jacobs had smoked PCP shortly before they
witnessed Fuller’s attack. In this context, it would not
have surprised the jury to learn that Eleby used PCP on
yet another occasion. Porter was a minor witness who was
also impeached at trial with evidence about changes in her
testimony over time, leaving little added significance to
the note that she changed her mind about having agreed
with Eleby’s claims. The jury was also well aware of
Jacobs’ vacillation, as she was impeached on the stand
with her shifting stories about what she witnessed.
Knowledge that a detective raised his voice during an
interview with her would have added little more. Nor do
we see how the note about the statement by Thomas’ aunt
could have mattered much, given the facts that neither
side chose to call the aunt as a witness and that the jury
already knew, from Thomas’ testimony, that his aunt had
told him not to tell anyone what he saw. As for James
Blue, petitioners argue that the investigators’ delay in
following up on Ammie Davis’ statement could have led
the jury to doubt the thoroughness of the investigation.
But this likelihood is seriously undercut by notes about
Davis’ demeanor and lack of detail, and by her prior false
accusations that Blue committed a different murder and
14                TURNER v. UNITED STATES

                      Opinion of the Court

that yet another person committed yet a different murder.
   We of course do not suggest that impeachment evidence
is immaterial with respect to a witness who has already
been impeached with other evidence. See Wearry v. Cain,
577 U. S. ___, ___–___ (2016) (per curiam) (slip op., at 7–9).
We conclude only that in the context of this trial, with
respect to these witnesses, the cumulative effect of the
withheld evidence is insufficient to “ ‘undermine confi-
dence’ ” in the jury’s verdict, Smith, 565 U. S., at 75–76
(quoting Kyles, 514 U. S., at 434; brackets omitted).
                              III
   On the basis of our review of the record, we agree with
the lower courts that there is not a “reasonable probabil-
ity” that the withheld evidence would have changed the
outcome of petitioners’ trial, id., at 434 (internal quotation
marks omitted). The judgment of the D. C. Court of Ap-
peals, accordingly, is affirmed.
                                               It is so ordered.

  JUSTICE GORSUCH took no part in the consideration or
decision of these cases.
 Cite as: 582 U. S. ____ (2017) 
     15

     Opinion
Appendix      of the of
         to opinion  Court
                        the Court 


         APPENDIX

                 Cite as: 582 U. S. ____ (2017)          1

                     KAGAN, J., dissenting

SUPREME COURT OF THE UNITED STATES
                         _________________

                  Nos. 15–1503 and 15–1504
                         _________________


     CHARLES S. TURNER, ET AL., PETITIONERS
15–1503               v.
                UNITED STATES

          RUSSELL L. OVERTON, PETITIONER
15–1504                  v.
                  UNITED STATES
 ON WRITS OF CERTIORARI TO THE DISTRICT OF COLUMBIA 

                  COURT OF APPEALS

                        [June 22, 2017] 


  JUSTICE KAGAN, with whom JUSTICE GINSBURG joins,
dissenting.
  Consider two criminal cases. In the first, the govern-
ment accuses ten defendants of acting together to commit
a vicious murder and robbery. At trial, each defendant
accepts that the attack occurred almost exactly as the
government describes—contending only that he wasn’t
part of the rampaging group. The defendants thus un-
dermine each other’s arguments at every turn. In the
second case, the government makes the same arguments
as before. But this time, all of the accused adopt a com-
mon defense, built around an alternative account of the
crime. Armed with new evidence that someone else perpe-
trated the murder, the defendants vigorously dispute the
government’s gang-attack narrative and challenge the
credibility of its investigation. The question this case
presents is whether such a unified defense, relying on
evidence unavailable in the first scenario, had a “reason-
able probability” (less than a preponderance) of shifting
2                TURNER v. UNITED STATES

                     KAGAN, J., dissenting

even one juror’s vote. Cone v. Bell, 556 U. S. 449, 452, 470
(2009); see Kyles v. Whitley, 514 U. S. 419, 434 (1995).
   That is the relevant question because the Government
here knew about but withheld the evidence of an alterna-
tive perpetrator—and so prevented the defendants from
coming together to press that theory of the case. If the
Government’s non-disclosure was material, in the sense
just described, this Court’s decision in Brady v. Maryland,
373 U. S. 83 (1963), demands a new trial. The Court today
holds it was not material: In light of the evidence the
Government offered, the majority argues, the transformed
defense stood little chance of persuading a juror to vote to
acquit. That conclusion is not indefensible: The Govern-
ment put on quite a few witnesses who said that the de-
fendants committed the crime. But in the end, I think the
majority gets the answer in this case wrong. With the
undisclosed evidence, the whole tenor of the trial would
have changed. Rather than relying on a “not me, maybe
them” defense, ante, at 6, all the defendants would have
relentlessly impeached the Government’s (thoroughly
impeachable) witnesses and offered the jurors a way to
view the crime in a different light. In my view, that could
well have flipped one or more jurors—which is all Brady
requires.
   Before explaining that view, I note that the majority
and I share some common ground. We agree on the uni-
verse of exculpatory or impeaching evidence suppressed in
this case: The majority’s description of that evidence, and
of the trial held without it, is scrupulously fair. See ante,
at 2–6, 7–9. We also agree—as does the Government—
that such evidence ought to be disclosed to defendants as a
matter of course. See ante, at 10. Constitutional require-
ments aside, turning over exculpatory materials is a core
responsibility of all prosecutors—whose professional inter-
est and obligation is not to win cases but to ensure justice
is done. See Kyles, 514 U. S., at 439. And finally, we
                 Cite as: 582 U. S. ____ (2017)           3

                     KAGAN, J., dissenting

agree on the legal standard by which to assess the materi-
ality of undisclosed evidence for purposes of applying the
constitutional rule: Courts are to ask whether there is a
“reasonable probability” that disclosure of the evidence
would have led to a different outcome—i.e., an acquittal or
hung jury rather than a conviction. See ante, at 10.
  But I part ways with the majority in applying that
standard to the evidence withheld in this case. That
evidence falls into three basic categories, discussed below.
Taken together, the materials would have recast the trial
significantly—so much so as to “undermine[] confidence”
in the guilty verdicts reached in their absence. Kyles, 514
U. S., at 434.
  First, the Government suppressed information identify-
ing a possible alternative perpetrator. The defendants
knew that, shortly before the police arrived, witnesses had
observed two men acting suspiciously near the alleyway
garage where Catherine Fuller’s body was found. But
they did not know—because the Government never told
them—that a witness had identified one of those men as
James McMillan. Equipped with that information, the
defendants would have discovered that in the weeks fol-
lowing Fuller’s murder, McMillan assaulted and robbed
two other women of comparable age in the same neighbor-
hood. And using that information, the defendants would
have united around a common defense. They would all
have pointed their fingers at McMillan (rather than at
each other), arguing that he committed Fuller’s murder as
part of a string of similar crimes.
  Second, the Government suppressed witness statements
suggesting that one or two perpetrators—not a large
group—carried out the attack. Those statements were
given by two individuals who walked past the garage
around the time of Fuller’s death. They told the police
that they heard groans coming from inside the garage; and
one remarked that the garage’s doors were closed at the
4                TURNER v. UNITED STATES

                     KAGAN, J., dissenting

time. Introducing that evidence at trial would have sown
doubt about the Government’s group-attack narrative,
because that many people (as everyone agrees) couldn’t
have fit inside the small garage. And the questions thus
raised would have further supported the defendants’
theory that McMillan (and perhaps an accomplice) had
committed the murder.
   Third and finally, the Government suppressed a raft of
evidence discrediting its investigation and impeaching its
witnesses. Undisclosed files, for example, showed that the
police took more than nine months to look into a witness’s
claim that a man named James Blue had murdered Fuller.
Evidence of that kind of negligence could easily have led
jurors to wonder about the competence of all the police
work done in the case. Other withheld documents re-
vealed that one of the Government’s main witnesses was
high on PCP when she met with investigators to identify
participants in the crime—and that she also encouraged a
friend to lie to the police to support her story. Using that
sort of information, see also ante, at 9, the defendants
could have undercut the Government’s witnesses—even
while presenting their own account of the murder.
   In reply to all this, the majority argues that “none of the
[accused] attempted to mount [an alternative-perpetrator]
defense” and that such a defense would have challenged
“the very cornerstone of the Government’s case.” Ante, at
12. But that just proves my point. The defendants didn’t
offer an alternative-perpetrator defense because the Gov-
ernment prevented them from learning what made it
credible: that one of the men seen near the garage had a
record of assaulting and robbing middle-aged women, and
that witnesses would back up the theory that only one or
two individuals had committed the murder. Moreover,
that defense had game-changing potential exactly because
it challenged the cornerstone of the Government’s case.
Without the withheld evidence, each of the defendants had
                 Cite as: 582 U. S. ____ (2017)           5

                     KAGAN, J., dissenting

little choice but to accept the Government’s framing of the
crime as a group attack—and argue only that he wasn’t
there. That meant the defendants often worked at cross-
purposes. In particular, each defendant not identified by a
Government witness sought to bolster that witness’s
credibility, no matter the harm to his co-defendants. As
one defense lawyer remarked after another’s supposed
cross-examination of a Government witness: “They’ve got
[an extra] prosecutor[ ] in the courtroom now.” Saperstein
& Walsh, 10 Defendants Complicate Trial, Washington
Post, Nov. 17, 1985, p. A14, col. 1. Credible alternative-
perpetrator evidence would have allowed the defendants
to escape this cycle of mutually assured destruction. By
enabling the defendants to jointly attack the Govern-
ment’s “cornerstone” theory, the withheld evidence would
have reframed the case presented to the jury.
   Still, the majority claims, an alternative-perpetrator
defense would have had no realistic chance of changing
the outcome because the Government had ample evidence
of a group attack, including five witnesses who testified
that they had participated in it or seen it happen. See
ante, at 12–13. But the Government’s case wasn’t nearly
the slam-dunk the majority suggests. No physical evi-
dence tied any of the defendants to the crime—a highly
surprising fact if, as the Government claimed, more than
ten people carried out a spur-of-the-moment, rampage-like
attack in a confined space. And as even the majority
recognizes, the Government’s five eyewitnesses had some
serious credibility deficits. See ibid. Two had been
charged as defendants, and agreed to testify only in ex-
change for favorable plea deals. See 116 A. 3d 894, 902
(D. C. 2015). Two admitted they were high on PCP at the
time. See id., at 903, 911; App. A535–A536, A649. (As
noted above, one was also high when she later met with
police to identify the culprits.) One was an eighth-grader
whose own aunt contradicted parts of his trial testimony.
6                TURNER v. UNITED STATES

                     KAGAN, J., dissenting

See 116 A. 3d, at 903, 911. Even in the absence of an
alternative account of the crime, the jury took more than a
week—and many dozens of votes—to reach its final ver-
dict. Had the defendants offered a unified counter-
narrative, based on the withheld evidence, one or more
jurors could well have concluded that the Government had
not proved its case beyond a reasonable doubt.
   Again, the issue here concerns the difference between
two criminal cases. The Government got the case it most
wanted—the one in which the defendants, each in an
effort to save himself, formed something of a circular firing
squad. And the Government avoided the case it most
feared—the one in which the defendants acted jointly to
show that a man known to assault women like Fuller
committed her murder. The difference between the two
cases lay in the Government’s files—evidence of obvious
relevance that prosecutors nonetheless chose to suppress.
I think it could have mattered to the trial’s outcome. For
that reason, I respectfully dissent.
