 United States Court of Appeals
         FOR THE DISTRICT OF COLUMBIA CIRCUIT



Argued September 20, 2019              Decided March 6, 2020

                         No. 18-3056

                UNITED STATES OF AMERICA,
                        APPELLEE

                              v.

       STEVEN MASON, ALSO KNOWN AS SAM MASON,
                     APPELLANT


        Appeal from the United States District Court
                for the District of Columbia
                   (No. 1:17-cr-00195-2)


    Gregory S. Smith, appointed by the court, argued the cause
and filed the briefs for appellant.

    Daniel J. Lenerz, Assistant U.S. Attorney, argued the
cause for appellee. With him on the brief were Jessie K. Liu,
U.S. Attorney, and Elizabeth Trosman and John P. Mannarino,
Assistant U.S. Attorneys.

    Before: ROGERS, GRIFFITH, and KATSAS, Circuit Judges.

    Opinion for the Court filed by Circuit Judge GRIFFITH.

    GRIFFITH, Circuit Judge: A jury convicted Steven Mason
and a codefendant of conspiring to deal heroin and other drugs.
                                2
Mason was sentenced to five years’ imprisonment, the
statutory mandatory minimum. On appeal, Mason argues that
the government violated its constitutional obligation under
Brady v. Maryland, 373 U.S. 83 (1963), to disclose material
helpful to his defense in a timely manner. Mason also objects
to the district court’s refusal to grant him a trial separate from
that of his codefendant. And he says the district court should
have found him eligible for a reduction of his sentence under
section 5C1.2 of the Sentencing Guidelines. We reject each of
Mason’s arguments and affirm his conviction and sentence.

                                 I

    Because Mason’s arguments are highly fact-bound, we
describe discovery, the trial, and sentencing in some detail.

                                A

     In 2016, a federal grand jury indicted Mason, Andrea
Miller, Nicholas Jones, Frank Walker, and several others for
their participation in a drug conspiracy. The government
alleged that Jones and Walker led a conspiracy that imported
drugs into the United States, then sold them to middlemen.
According to the government, Mason was one of the
middlemen and Miller received a shipment of drugs at her
home.

     Although most of the conspirators pleaded guilty, Mason
and Miller did not. The government filed a new two-count
indictment against them in October 2017. The first count
charged Miller with conspiracy to import heroin and Xanax.
The second charged Mason and Miller with conspiracy to
distribute heroin, Xanax, and fentanyl. Mason sought to
separate his trial from Miller’s, but the district court denied his
motion and set their joint trial to begin in January 2018.
                               3

     Problems arose in December 2017, when the government
made a series of disclosures that suggested that Nicholas Jones,
who was likely to appear as a key government witness, might
lie at the trial. In early March 2017, the government learned of
a rumor that a member of the conspiracy had written a letter
reporting that he planned to tell lies about Walker’s role and
that Walker had a copy of the letter. The government suspected
that Jones wrote the letter but he denied that he was the author
when asked during a March 10 interview. In May, the
government asked Jones about the letter again, this time with
the aid of a polygraph. Although he denied authorship, the
polygraph suggested he was lying.

     In a June interview, the previously uncooperative Walker
gave the government the handwritten letter, which described its
author’s plan to “go down there and lie on everybody.”
According to Walker, Robert Bethea, a fellow inmate whose
nickname was “Jazz,” told Walker in February that Jones had
written the letter. Jazz gave the letter to Walker later that
month.

      Neither counsel for Mason nor Miller knew any of this
until disclosed by the government on the eve of trial in
December 2017. Displeased by this late disclosure, they moved
for dismissal of the indictment, arguing that the government
had violated its Brady obligation to timely disclose material
helpful to them. Defense counsel also set out to find Jazz,
whose testimony might link Jones to the letter undermining his
credibility. They soon discovered, however, that Jazz had died
of a drug overdose in April 2017, shortly after his release from
jail.

    Jazz’s death limited the letter’s value to the defense. So,
too did the “conclusive” determination of the government’s
                               4
handwriting expert that Jones did not write the letter, the
district court’s ruling that defense counsel could not refer to
Jones’s failed polygraph, and Walker’s refusal to testify,
invoking the protection of the Fifth Amendment.

     The district court denied the Brady motion on the ground
that Mason and Miller suffered no prejudice from the belated
disclosure. The government “didn’t have an opportunity to
review the letter until June 2017, at which point Jazz had
already died,” the court found. “So the defense would not have
had an ability to interview Jazz had the government disclosed
this information in June when they should have.” Tr. of Pretrial
Hr’g (Jan. 29, 2018) at 31:22-32:1, J.A. 248-49. To allow the
defense additional time to prepare, the court continued the trial
for more than a month.

                               B

     The seven-day jury trial against Mason and Miller began
on February 26, 2018. The government presented its case
against Miller first, with testimony that showed Miller had
allowed Jones to ship drugs to her home. Before the
government began its case against Mason, the court received
the following note from Juror #1:

    Your Honor, would it be possible for the government to
    ask Mr. Jones, one, why did he or Mr. Walker choose
    Mr. Mason’s house for drug delivery? And two, did he or
    Mr. Walker have a personal relationship with Mr. Mason
    or was this address picked at random?

Tr. of Jury Trial (Mar. 2, 2018) at 795:3-10, J.A. 874. The court
acknowledged that the note was “concerning,” as the
government had never suggested that Mason’s house was used
for drug delivery. “[I]t seems to me that at least one juror is
                               5
confused and thinks that Mr. Mason lives at [Miller’s address].
I don’t know how.” Id. at 794:12, 795:11-13, J.A. 873-74. The
court instructed the jury that its “question may be resolved
through the remainder of the evidence.” If not, the court said,
the jury should send another note “at the close of the evidence.”
Id. at 802:12-14, J.A. 881.

     Shortly after the court’s instruction, the government asked
Jones whether he knew Mason’s address. Jones answered no.
Id. at 807:18-808:1, J.A. 886-87. Mason renewed his motion
for severance, this time citing the juror note as evidence of
prejudice, but the court denied the motion. No juror ever sent a
follow-up note on the subject.

      The government then presented its case against Mason,
including testimony by Jones and wiretapped phone calls in
which Mason and his coconspirators discussed dealing drugs.
Concerned that Jones would deny authorship and that the
government would bolster that denial with the testimony of its
handwriting expert, defense counsel never used the letter at
trial. The jury found Mason and Miller guilty of all charges
other than those related to fentanyl, on which the court had
granted a judgment of acquittal.

                               C

     Before sentencing, Mason sought to qualify for the
Sentencing Guidelines’ “safety valve,” which would allow him
to avoid a five-year mandatory minimum sentence if he fully
debriefed the government on his “offense of conviction and all
relevant conduct.” U.S.S.G. § 5C1.2 cmt. n.3. During the
debriefing interview, Mason was asked about his associates in
the drug trade. Mason refused to answer, saying he didn’t want
to “put someone else in the line of fire.”
                                6
     At sentencing, the government cited Mason’s refusal to
name his drug suppliers or customers as reason to find him
ineligible for the safety valve. The district court agreed and
sentenced Mason to five years’ imprisonment.

     This timely appeal of his conviction and sentence
followed. The district court had jurisdiction under 18 U.S.C.
§ 3231, and we have jurisdiction under 28 U.S.C. § 1291.

                                II

                                A

     Mason argues that the government’s belated disclosure of
what it knew about the handwritten letter violated his
constitutional rights under Brady v. Maryland. He asks that we
vacate his conviction and direct the district court to dismiss the
indictment or remand for a new trial. Because the relevant facts
are uncontested, our review of Mason’s Brady claim is de novo.
See United States v. Sitzmann, 893 F.3d 811, 821 (D.C. Cir.
2018) (per curiam).

    A Brady violation has three parts. “The evidence at issue
must be favorable to the accused, either because it is
exculpatory, or because it is impeaching; that evidence must
have been suppressed by the State, either willfully or
inadvertently; and prejudice must have ensued.” Strickler v.
Greene, 527 U.S. 263, 281-82 (1999).

     Information about the letter was favorable to Mason
because it tended to impeach Jones, a government witness
against him. The government suppressed its knowledge of the
letter by postponing disclosure for months, until trial was
imminent. See United States v. Pasha, 797 F.3d 1122, 1133
(D.C. Cir. 2015). At oral argument, the government declined to
                                7
“defend[] the timeliness” of its disclosure and conceded that it
had “made a misjudgment as to the amount of time that the
Defense needed” to use the information disclosed. Tr. of Oral
Arg. at 25:12, 33:25-34:1. We agree. The government’s delay
was “inexcusable.” Pasha, 797 F.3d at 1133.

     But even a grossly belated disclosure does not violate
Brady unless the defendant suffers prejudice from the delay.
Prejudice exists only if there is “a reasonable probability
that . . . the result of the proceeding would have been different”
had the disclosure occurred earlier. Strickler, 527 U.S. at 280
(quoting United States v. Bagley, 473 U.S. 667, 682 (1985)). A
“‘probability’ reaches the level of ‘reasonable’ when it is high
enough to ‘undermine confidence in the verdict.’” United
States v. Johnson, 592 F.3d 164, 170 (D.C. Cir. 2010) (quoting
Kyles v. Whitley, 514 U.S. 419, 435 (1995)). “The defendant
bears the burden of showing a reasonable probability of a
different outcome.” United States v. Johnson, 519 F.3d 478,
488 (D.C. Cir. 2008).

     Mason asserts three forms of prejudice from the belated
disclosure. First, he says, “earlier production of the letter would
have kept defense counsel from being hamstrung by the time
constraints that later arose in the waning weeks before trial.”
Mason Br. 35. That argument fails, because a continuance of
reasonable length negates any prejudice arising from time
constraints alone. See, e.g., United States v. Halloran, 821 F.3d
321, 341-42 (2d Cir. 2016). The district court granted Mason
such a continuance.

    Mason next argues that an earlier disclosure of what the
government knew about the letter might have provided defense
counsel with promising leads. Perhaps, he says, defense
counsel would have uncovered cellmates who overheard a
conversation between Jazz and Jones about the letter had they
                               8
investigated the matter earlier in 2017. See Tr. of Oral Arg. at
40:7-8. Maybe Walker, had he been interviewed earlier, would
have been willing to testify as to what Jazz told him about the
letter, instead of pleading the Fifth. See id. at 6:12-7:17. Or
defense counsel might “have subpoenaed . . . and monitored
[Jazz] . . . so [that] he never died.” Id. at 12:9-13.

     Maybe so. But “mere speculation is not sufficient to
sustain a Brady claim.” United States v. Horton, 756 F.3d 569,
575 (8th Cir. 2014) (internal quotation marks and citations
omitted). Hypothesizing that certain “information, had it been
disclosed to the defense, might have led [defense] counsel to
conduct additional discovery that might have led to some
additional evidence that could have been utilized” is
disfavored. Wood v. Bartholomew, 516 U.S. 1, 6 (1995) (per
curiam) (describing such reasoning as “mere speculation, in
violation of the standards” the Supreme Court has established
for Brady claims). The argument that an earlier disclosure
might have led Mason to uncover other promising leads is
simply too speculative to undermine our confidence in the
outcome of the trial.

     Last, Mason argues that with an earlier disclosure he could
have “found and interviewed” Jazz, Mason Br. 35, who might
have provided statements that were “admissible as
impeachment evidence,” Reply Br. 8. We can assume, for the
sake of argument, that the government should have disclosed
its knowledge of the rumored letter in March 2017, before
Jazz’s death in April. Even so, Mason fails to show that the
defense he presented at trial differed in any meaningful way
from the defense he could have presented if he had interviewed
Jazz. If Mason’s defense would have been the same regardless,
he cannot meet his burden of showing a “reasonable probability
of a different outcome” at trial, Johnson, 519 F.3d at 488, and
his Brady claim fails.
                               9

      Mason’s principal obstacle is the rule against hearsay. See
Gov’t Br. 29. Even assuming that an earlier disclosure would
have led to an interview with Jazz, and that such an interview
would have provided grounds to impeach Jones, Mason fails to
show how the out-of-court statements of a deceased declarant
would have helped him at trial. Such statements would have
been obvious hearsay if offered for the truth of the matter
asserted—that Jones had written the letter—and inadmissible
at trial unless subject to an enumerated hearsay exception. See
FED. R. EVID. 801, 802; see also 30B CHARLES ALAN WRIGHT
ET AL., FEDERAL PRACTICE AND PROCEDURE § 6728 (2018 ed.).

     Mason says that any of three hearsay exceptions would
have allowed the court to admit Jazz’s hypothetical statements:
the exception for dying declarations, the exception for
statements against interest, and the residual exception. See
Reply Br. 8. We disagree. The exception for dying declarations
does not apply because Jazz’s statements would have had
nothing to do with the “cause or circumstances” of his death.
FED. R. EVID. 804(b)(2). The exception for statements against
interest is unavailing as well. Mason offers no argument why
statements naming Jones as the letter’s author would have been
“so contrary to [Jazz’s] proprietary or pecuniary interest or had
so great a tendency . . . to expose [Jazz] to civil or criminal
liability,” id. 804(b)(3)(A), that they should qualify under that
exception.

     The residual exception fares no better. We apply this
“extremely narrow” exception “sparingly,” “only in the most
exceptional circumstances,” and only if the out-of-court
statement is both “very important and very reliable.” United
States v. Slatten, 865 F.3d 767, 807 (D.C. Cir. 2017) (per
curiam) (internal quotation marks and citations omitted). We
can grant that a statement by Jazz impeaching Jones might have
                                 10
been “very important” to Mason’s defense, but it would have
been of doubtful reliability. Mason argues that the requisite
“indicia of reliability” would come from the statements of
others that Jazz had told them Jones wrote the letter. Tr. of Oral
Arg. at 12:16-24; 39:18-23. But we doubt that more hearsay
from Jazz would provide the “sufficient guarantees of
trustworthiness” the residual exception requires. FED. R. EVID.
807(a)(1). And in any event, the government could undermine
any showing of reliability with the handwriting expert’s
“conclusive” determination that Jones didn’t write the letter. *

     Of course, defense counsel might have relied on Jazz’s
statements to question Jones during cross-examination. See,
e.g., United States v. Whitmore, 359 F.3d 609, 621-22 (D.C.
Cir. 2004). But we doubt such a tack would have been effective
here. Defense counsel could have cross-examined Jones using
their knowledge of the letter, but they declined. Moreover, the
use of additional statements from Jazz to impeach Jones was
unlikely to have improved the cross much, as Jones could deny
authorship all the same. And defense counsel feared the
government would bolster that denial with its “conclusive”
handwriting analysis. See Mason Br. 12, 36. Given the
circumstances of this case, we see no “reasonable probability
of a different outcome,” Johnson, 519 F.3d at 488, from such
an exchange.

    We hold that Mason has failed to demonstrate prejudice
from the government’s belated disclosure and that his Brady

*
  In the alternative, Mason argues that even if the interview yielded
no admissible evidence it might have revealed the identity of Jazz’s
“uncle,” a “potential additional (living) witness to these matters”
who was mentioned, but never named, in the handwritten letter.
Reply Br. 8-9. Again, the possibility that additional information
about an unknown person might have helped Mason’s defense is
simply too speculative to undermine our confidence in the verdict.
                               11
claim thus fails. That holding is consistent with our decision in
United States v. Pasha, 797 F.3d 1122 (D.C. Cir. 2015), in
which the government waited eight months to disclose that an
eyewitness had made statements favorable to the defense. By
the time defense counsel interviewed the eyewitness, he said
his memory had faded; he was no longer useful to the defense.
We held that one of the defendants, against whom the evidence
was particularly weak, was prejudiced by the belated disclosure
and thus had a valid Brady claim.

     Pasha differs from Mason’s case. For one, the defendant
in Pasha demonstrated how an earlier interview with the
eyewitness would have helped her. Had she taken “a sworn
statement from [the eyewitness] when his memory was fresh,”
at trial the eyewitness might have read that statement into
evidence as a recorded recollection. Reply Brief for Appellant
Daaiyah Pasha at 20, Pasha, 797 F.3d 1122 (No. 13-3024),
2015 WL 831935; FED. R. EVID. 803(5). That option was
unavailable to Mason because Jazz could not testify under any
circumstances. Further, the government’s case against the
defendant who prevailed on her Brady claim in Pasha was not
strong. See 797 F.3d at 1137 (describing the “weak evidence”
that the defendant participated in the crime). Mason’s
incriminating wiretapped statements, through which the jury
heard Mason himself make several thinly veiled references to
dealing drugs, distinguish this case from Pasha. See Mason Br.
22 (acknowledging that these wiretaps were “obviously the
Government’s strongest evidence against” him).

                               B

     Mason objects to the district court’s denial of his motions
for misjoinder and severance. The purpose of both motions is
the same: to separate a defendant’s trial from his codefendant’s.
Because severance, unlike misjoinder, can require a court to
                               12
consider events that occurred at trial, we review the denial of a
severance motion for abuse of discretion and the denial of a
misjoinder motion de novo. See United States v. Bikundi, 926
F.3d 761, 781 (D.C. Cir. 2019) (per curiam); United States v.
Bostick, 791 F.3d 127, 145 (D.C. Cir. 2015).

                                1

    In his pretrial motion for misjoinder, Mason argued that
the indictment improperly joined his trial with that of his
codefendant Andrea Miller. He and Miller “were merely two
small spokes in a larger drug conspiracy,” he says, who did not
conspire “together” at all. Mason Br. 38.

     We have a “broad policy favoring initial joinder.” United
States v. Perry, 731 F.2d 985, 991 (D.C. Cir. 1984). Under
Federal Rule of Criminal Procedure 8(b), an indictment “may
charge 2 or more defendants if they are alleged to have
participated in the same act or transaction, or in the same series
of acts or transactions, constituting an offense or offenses.” Our
Rule 8 “[j]oinder analysis ‘does not take into account the
evidence presented at trial,’ but rather ‘focuses solely on the
indictment and pre-trial submissions.’” Bostick, 791 F.3d at
145 (quoting United States v. Gooch, 665 F.3d 1318, 1334
(D.C. Cir. 2012)).

    The indictment’s allegation that Mason and Miller
conspired to distribute drugs made joinder of their trials proper.
“The mere allegation of a conspiracy presumptively satisfies
Rule 8(b), since the allegation implies that the defendants
named have engaged in the same series of acts or transactions
constituting an offense.” United States v. Friedman, 854 F.2d
535, 561 (2d Cir. 1988) (quoting United States v. Castellano,
610 F. Supp. 1359, 1396 (S.D.N.Y. 1985)). We have frequently
held that participation in the same charged conspiracy justifies
                               13
joinder. See, e.g., United States v. McGill, 815 F.3d 846, 905
(D.C. Cir. 2016); United States v. Spriggs, 102 F.3d 1245,
1255-56 (D.C. Cir. 1996).

     We reject Mason’s argument that the indictment falsely
alleged that he and Miller conspired “together.” The allegation
that the two “did knowingly and willfully combine, conspire,
confederate and agree together” and with others to distribute
heroin and other drugs, Indictment (Oct. 17, 2017) at 2, J.A.
24, is nothing more than an allegation that Mason and Miller
participated in the same conspiracy, which they did. We also
reject Mason’s argument that “the prosecution’s own
statements made at trial later plainly revealed” that Mason and
Miller’s “‘acts and transactions’ did not overlap at all.” Mason
Br. 39. “If the indictment establishes proper joinder under Rule
8(b), trial evidence cannot render joinder impermissible and is
thus irrelevant to our inquiry.” United States v. Moore, 651
F.3d 30, 69 (D.C. Cir. 2011) (per curiam), aff’d sub nom. Smith
v. United States, 568 U.S. 106 (2013).

                                2

      Under Federal Rule of Criminal Procedure 14(a), a district
court may sever codefendants’ trials if joinder “appears to
prejudice a defendant.” Mason says severance was required for
two reasons: the “generalized prejudice” he faced from a joint
trial with Miller and the “specific prejudice” that arose from
the “confusion” demonstrated by the note from Juror #1.
Mason Br. 40.

     We disagree. We recognize that in some joint trials, the
risk of prejudice to one coconspirator is so great that Rule 14(a)
requires severance even where joinder was proper. For
instance, severance may be appropriate when coconspirators
are accused of “grossly disparate crimes,” United States v.
                                 14
Sampol, 636 F.2d 621, 645 (D.C. Cir. 1980) (per curiam), or
when there is great “disproportion in the evidence,” United
States v. Mardian, 546 F.2d 973, 980 (D.C. Cir. 1976) (en
banc).

     This is not one of those cases. Mason and Miller were
jointly charged with conspiracy to distribute drugs. Miller
alone was charged with conspiracy to import drugs. Those are
not grossly disparate crimes. See Sampol, 636 F.2d at 647
(requiring severance where defendant was accused of making
false declarations and misprision of felony and codefendants
were accused of “crimes of conspiracy to assassinate and
murder”). Nor was there such disproportion in the evidence that
severance was warranted. The government presented evidence
of international drug trafficking during its case against Miller.
But much of the same might have been introduced at a trial
against Mason alone to prove he had conspired to distribute a
significant quantity of heroin. See McGill, 815 F.3d at 947;
United States v. Law, 528 F.3d 888, 906 (D.C. Cir. 2008).

     Nor did the district court abuse its discretion in denying
Mason’s motion for severance after it received the juror note.
Over the course of the trial, the district court and the
government took appropriate steps to make sure that the
confusion revealed in the note was addressed. The government
presented its cases against Miller and Mason separately. After
receiving the note, the district court issued an appropriate
instruction and the government promptly elicited testimony to
dispel the juror’s confusion. At the close of the trial, the district
court instructed the jury that it was required to consider the
evidence separately against each defendant. See Tr. of Jury
Trial (Mar. 6, 2018) at 1326:1-5, 1336:5-14, J.A. 1405, 1415.
Those steps sufficed to dispel any confusion about the different
roles of Mason and Miller in the conspiracy.
                               15
     Mason argues that “there can be no assurance that the
spillover prejudice that we clearly know Juror #1 harbored . . .
was in fact later purged” and that “[n]othing whatsoever
reveals that Juror #1 did not vote to convict based at least in
part on this mistaken understanding of the evidence.” Mason
Br. 42. That may be true. But Mason misunderstands the scope
of our review. We do not ask whether we are certain no juror
voted to convict based on a mistaken understanding of the
evidence, a fact neither we nor the district court could know.
We ask only whether the district court abused its discretion in
denying his motions for severance. It did not.

                               C

     Last, Mason challenges the district court’s finding that he
is ineligible for the safety valve provision of the Sentencing
Guidelines. Under that provision, certain defendants who
“truthfully provide[] to the Government all information and
evidence” they possess concerning their “offense of conviction
and all relevant conduct” may be sentenced without regard to a
mandatory minimum. U.S.S.G. § 5C1.2(a)(5) & cmt. n.3. At
sentencing, the government objected to Mason’s refusal to
name his other drug suppliers and the customers who
purchased drugs from him. Mason argues the government and
the district court expected him to provide more information
than the safety valve requires. Because the breadth of the safety
valve is a legal, not factual, question, we review the district
court’s finding de novo. See United States v. Vega, 826 F.3d
514, 538 (D.C. Cir. 2016) (per curiam).

     As part of his blanket refusal to “put someone else in the
line of fire,” Mason refused to name the persons to whom he
sold the drugs he obtained from Jones and Walker. According
to the government, those customers would have been
“significant mid-level dealers, purchasing 20 to 50 grams of
                               16
heroin, worth thousands of dollars, at a time.” Gov’t Br. 61.
Their names constituted “information” concerning “the offense
of conviction and all relevant conduct” that Mason was
obligated to provide. See United States v. Wrenn, 66 F.3d 1, 3
(1st Cir. 1995) (affirming a finding of safety valve ineligibility
for a drug-dealing defendant who refused to name his
customers). Refusing to disclose the names of his customers
disqualified Mason from taking advantage of the safety valve.

                               III

    For the foregoing reasons, we affirm Mason’s conviction
and sentence.

                                                     So ordered.
