United States <strong>v</strong>. Roman Sterlingov

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United States Court of Appeals
         FOR THE DISTRICT OF COLUMBIA CIRCUIT



Argued May 12, 2026               Decided September 25, 2026

                        No. 24-3161

                UNITED STATES OF AMERICA,
                        APPELLEE

                             v.

                   ROMAN STERLINGOV,
                      APPELLANT



        Appeal from the United States District Court
                for the District of Columbia
                   (No. 1:21-cr-00399-1)



     Tor Ekeland argued the cause for appellant. With him on
the briefs were Marc Fernich, Maksim Nemtsev, Daniel Aaron,
and Amy C. Collins.

    Joseph A. Scrofano was on the brief for amicus curiae
Chainargos in support of appellant.

    Jenny C. Ellickson, Attorney, U.S. Department of Justice,
argued the cause for appellee. With her on the brief was
Jeanine Ferris Pirro, U.S. Attorney. David M. Lieberman and
Scott A. Meisler, Attorneys, entered appearances.
                               2
    Karl J. Mihm and Aileen M. McGrath were on the brief for
amicus curiae Chainalysis, Inc. in support of appellee.

    Before: MILLETT, PILLARD, and WILKINS, Circuit Judges.

    Opinion for the Court filed by Circuit Judge WILKINS.

     WILKINS, Circuit Judge: Appellant Roman Sterlingov, a
dual Swedish-Russian national, was accused of creating and
operating a bitcoin “mixer” called Bitcoin Fog for the sole
purpose of aiding money laundering and hiding illicit activity.
After a jury trial, Sterlingov was convicted of one count of
conspiracy to commit money laundering under
18 U.S.C. §
1956
(h) (“Count I”), one count of substantive money
laundering under
18 U.S.C. § 1956
(a)(3)(A) and (B) (“Count
II”), one count of operating an unlicensed money transmitting
business under
18 U.S.C. § 1960
(a) (“Count III”), and one
count of conducting a money transmission business without a
license in violation of
D.C. Code § 26-1023
(c) (“Count IV”).
He now appeals his convictions, as well as his 150-month
imprisonment sentence, advancing numerous arguments to
reverse and vacate the judgment below. We have considered
each of those arguments and find none of them meritorious.
Accordingly, we affirm the District Court.

                               I.

     Some general background and definitions are necessary to
understand the prosecution’s theory and Sterlingov’s
contentions. This case involves the use of bitcoin, which refers
to both the most common form of cryptocurrency, as well as a
“a system that facilitates financial transactions.” App. 6690
(citation modified). Bitcoin as a unit of virtual currency is
“transacted over the Internet using bitcoin software,” which
allows “users to create bitcoin addresses, roughly analogous to
                               3
anonymous accounts, and to securely transfer bitcoin from one
bitcoin address to another.”
Id.
(citation modified). Relatedly,
“bitcoin the system is a peer-to-peer network enabling proof
and transfer of ownership . . . [of bitcoin] without involving a
third-party such as a bank.”
Id.
(citation modified). Bitcoin
transactions are anonymous—the sending address(es),
receiving address(es), and transaction ID(s) are identified only
by a long set of numbers and letters. The transactions are also
public—the above-mentioned information, as well as the
amount exchanged and the timing of the exchange are all
visible on the blockchain, which is publicly accessible to
anyone who has a hankering to investigate bitcoin transactions.

     The anonymity built into bitcoin and the blockchain can
be manipulated to obfuscate illicit transactions. Those who
intend to use cryptocurrency for criminal purposes sometimes
use bitcoin “mixers.” Mixers generally operate by allowing
multiple users to deposit bitcoin into a shared pool and then
withdraw funds from that same shared pool. This mixing
makes it difficult for anyone following the transaction history
to trace a specific deposit to a later withdrawal. Moreover, the
casual observer of a blockchain would not be able to discern
who made a deposit because the sending/receiving addresses
memorialized on the blockchain do not use real-world
identities, nor would the casual observer be able to tell whether
the same person who deposited bitcoin later withdrew those
funds from the mixer, since all of the deposits have been pooled
together. Law enforcement officials, however, have created
new tools to help investigate potentially illicit bitcoin
transactions, including by “clustering” bitcoin addresses and
associating those clusters with known users or entities.

    Bitcoin mixers can operate on something known as the
“darknet,” “a collection of hidden websites accessible only
through anonymization software that obscures users’ internet
                               4
protocol addresses by filtering their traffic through a network
of relay computers called the Tor network.” United States v.
Harmon,
474 F. Supp. 3d 76
, 82 (D.D.C. 2020) (citation
modified). Within the darknet are marketplaces, which
“operate similarly to ordinary internet marketplaces” like
Amazon or eBay wherein vendors sell items and sometimes
communicate with potential buyers to execute transactions.
United States v. Le,
902 F.3d 104, 107
(2d Cir. 2018). While
such marketplaces can function for legitimate purposes, the
“transactions overwhelmingly involve contraband.”
Id.
At the center of this tale is a bitcoin mixer named “Bitcoin
Fog,” launched in 2011 by someone identifying himself as
“Akemashite Omedetou”—who the government alleges is
actually Roman Sterlingov. The government asserted that
Sterlingov, using this alias, created Bitcoin Fog for the purpose
of evading government oversight and facilitating illicit
transactions. To support its theory, the government introduced
evidence during trial allegedly tying Sterlingov to Bitcoin Fog.
This evidence included an internet protocol (“IP”) analysis that
identified IP addresses connected to Sterlingov that interacted
with Bitcoin Fog, Sterlingov’s 2011 activity wherein he
appeared to express interest in other bitcoin mixers, and
Sterlingov’s promotion of illegal activities on the darknet in
2012, recommending that users buy drugs from a darknet site
called Silk Road.

     Sterlingov and Bitcoin Fog’s alleged connection to darknet
vendors like Silk Road also became a central tenet of the
government’s theory of the case, particularly its theory of
conspiracy. To support its assertions that Sterlingov engaged
in the charged crimes, the government presented evidence of a
bitcoin clustering analysis that tied Bitcoin Fog to over 900,000
addresses that were engaging with other darknet vendors also
selling illicit products. These darknet vendors included Silk
                               5
Road, AlphaBay, Agora, Nucleus, Abraxas, Pandora
Openmarket, Sheep, Black Bank, and Welcome to Video, all
of which both directly sent bitcoin and directly received bitcoin
from Bitcoin Fog.

     The government also presented additional evidence
regarding Bitcoin Fog’s operations and how they were
purposefully created to hide illicit conduct, including how
Bitcoin Fog deleted its records every week, and how Bitcoin
Fog fees were charged on a randomized basis to prevent
investigators from calculating precise withdrawals. Bitcoin
Fog’s hallmarks for obfuscating criminal activity were lauded
by Akemashite Omedetou, who described the platform as a
service that would “never be found” and would “not cooperate
with any authorities,” with Bitcoin Fog’s public website further
highlighting that the platform made “it impossible to prove any
connection between a deposit and a withdraw[al].” App. 2777–
78, 3721.

     Between 2011 and Sterlingov’s arrest in 2021, Sterlingov
had approximately 40 financial accounts, which collectively
received total bitcoin deposits of approximately $1.8 million.
At the time of his arrest at Los Angeles International Airport in
April 2021, marking only his second trip to the United States,
Sterlingov had bitcoin in a wallet stored on his phone worth
more than $500,000. App. 3924–26. Bitcoin Fog also stopped
operating two days after Sterlingov was arrested, with the last
withdrawal occurring on April 29, 2021. A jury convicted
Sterlingov of Counts I through IV, and the District Court
sentenced him to 150 months’ imprisonment. Sterlingov now
appeals. We have jurisdiction to review under
28 U.S.C. §
1291
and
18 U.S.C. § 3742
(a).
                                6
                               II.

    Sterlingov raises a number of grounds to vacate his
conviction. We consider and reject each of those in turn below.

                           A. Venue

      The Constitution requires that crimes be tried “in the State
where the . . . Crimes shall have been committed.” U.S. CONST.
art. III, § 2, cl. 3; see id. amend. VI. The Supreme Court has
interpreted that requirement to mean that “a trial may be held
where any part of a crime can be proved to have been done,”
even if the chosen district is not “the district in which [the
defendant] is personally at the time of committing the crime.”
Smith v. United States,
599 U.S. 236
, 243–44 (2023) (citation
modified). Sterlingov asserts that venue is unconstitutional in
the District of Columbia (“D.C.”) for all four charges levied
against him. He originally raised these objections in a motion
to dismiss for lack of venue. The District Court denied the
motion, finding that “the indictment adequately allege[d]
venue.” App. 2629. However, as Sterlingov timely challenged
venue and raised a genuine issue of fact material to the crime’s
connection to D.C., the District Court found that venue was
also a jury question at trial. United States v. Sitzmann,
893 F.3d
811, 824
(D.C. Cir. 2018) (per curiam). Under our precedent,
the government had to demonstrate to the jury by a
preponderance of the evidence that venue is proper. United
States v. Slatten,
865 F.3d 767, 786
(D.C. Cir. 2017) (per
curiam). At this juncture, where a defendant has renewed his
objections to venue, “this Court views the evidence in the light
most favorable to the government.”
Id. at 786
(citation
omitted). Under these principles, we hold that venue is proper
in D.C. for all four Counts.
                               7
     Key to the question of venue is a sting operation conducted
by Special Agent Matthew Price in D.C. In 2019, Agent Price
created a Bitcoin Fog account, deposited approximately $250
worth of bitcoin, and then withdrew almost all of it the next
day. Bitcoin Fog sent a message upon the submission of Agent
Price’s withdrawal request saying that the payment had been
completed successfully, and that any record of the transaction
would be “removed from [its] logs.” App. 2853. A few months
later, in November 2019, Agent Price conducted another
undercover transaction, sending bitcoin to his Bitcoin Fog
account from an account that he had created on a darknet
market. The following day, he sent a message to Bitcoin Fog’s
administrators via the chat function stating that he had “created
[his] account to clean [his] coins from selling ecstasy” and that
he had “more coins” to “clean[],” but that he wasn’t sure
whether he could trust the platform. App. 2870–71. Two days
later, Agent Price had not received any response to his
message, but he proceeded to withdraw his funds anyway,
which prompted a message stating that the payment was
complete.

         1. Count II – Substantive Money Laundering

     Keeping the above series of facts in mind, we begin
slightly out of order with Count II, the substantive money
laundering charge. Count II of the indictment charged
Sterlingov under
18 U.S.C. § 1956
(a)(3)(A) and (B), which
impose criminal liability on anyone who “conducts or attempt
to conduct a financial transaction involving property
represented to be the proceeds of specified unlawful activity,
or property used to conduct or facilitate specified unlawful
activity” with the intent to “promote the carrying on of
specified unlawful activity” or “conceal or disguise the nature,
location, source, ownership, or control of property believed to
be the proceeds of specified unlawful activity.” The statute
                                8
contains a venue provision that states that venue is proper in
“any district in which the financial or monetary transaction is
conducted.”
Id.
§ 1956(i)(1)(A). The statute further specifies
that a “transfer of funds from 1 place to another” constitutes “a
single, continuing transaction,” and a person who conducts
“any portion of [a] transaction may be charged in any district
in which the transaction took place.”
18 U.S.C. § 1956
(i)(3).
The government asserts that because Agent Price represented
to Bitcoin Fog that the money he was sending into the platform
was the result of illegal ecstasy sales—i.e., “specified unlawful
activity”—and because Agent Price was able to withdraw his
money from the platform a few days later, while sitting in his
office in D.C., venue is proper in that jurisdiction. We agree.
Sufficient evidence presented at trial allowed the jury to find
that Agent Price received the purported laundered funds in
D.C., including his own testimony, as well as photos and videos
of his interactions with Bitcoin Fog.

      Sterlingov claims that venue cannot rest on such grounds
because the government did not demonstrate that Bitcoin Fog
administrators would have known that the bitcoin Agent Price
deposited was the result of “specified unlawful activity.”
Sterlingov’s argument is two-fold: First, the mere fact of
bitcoin being sent to Bitcoin Fog does not establish that the
funds were illicit; and second, because the government had not
presented any evidence that Bitcoin Fog’s administrators saw
the messages from Agent Price regarding his desire to launder
illicit funds, it had further not established that Sterlingov knew
he was promoting or concealing unlawful activity. This is a
challenge to the sufficiency of the government’s proof that
Sterlingov ever saw Agent Price’s message, which goes to guilt
rather than to whether venue is constitutional in D.C.
Regardless, the challenge fails. The government presented
evidence that Sterlingov was the administrator of Bitcoin Fog
and that the chat function on Bitcoin Fog was operational and
                               9
provided a means to communicate with the mixer’s
administrator. The jury could reasonably infer from such
evidence that Sterlingov or another coconspirator saw Agent
Price’s message.

    In sum, we hold that venue for Count II is proper in D.C.

          2. Count I – Conspiracy to Money Launder

     We now turn to Count I, conspiracy to commit money
laundering under
18 U.S.C. § 1956
(h). The statute provides
that venue is proper for conspiracy either “in the district where
venue would lie for the completed offense under” § 1956(i)(1)
“or in any other district where an act in furtherance of
the . . . conspiracy took place.” Id. § 1956(i)(2). The
government’s theory for conspiracy was that “Sterlingov or a
co-conspirator allegedly mixed the [undercover] agent’s
Bitcoin and transferred it to a receiving account after being
informed that the Bitcoin was the proceeds of an ecstasy sale
on the darknet market[.]” App. 2635. In light of this theory,
because Sterlingov transferred bitcoin to and from Agent Price
in D.C., and thereby furthered the conspiracy in that
jurisdiction, venue was proper for Count I. The involvement
of an undercover agent rather than an alleged conspirator in
triggering the illicit action does not negate this conclusion, so
long as the government proved by a preponderance of the
evidence that Sterlingov took an action in furtherance of the
conspiracy by transferring bitcoin to D.C. See Sitzmann,
893
F.3d at 820, 826
(affirming district court’s venue finding based
on co-conspirator’s wire transfer to government informant in
D.C.). Here, as mentioned above, the government presented a
plethora of evidence establishing that transfer of funds to and
from Bitcoin Fog furthered Bitcoin Fog’s ability to launder the
funds of all users.
                                  10
     Sterlingov’s main rebuttal is that the “District
Court . . . erred by instructing the jury that an overt act by a
Government agent could establish venue for a conspiracy as to
Count [I].” Appellant Br. at 22. According to Sterlingov,
because the indictment alleged that the government mixed
Bitcoin in D.C. only in Count II, that action could not “serve as
the basis for venue for Count [I].”
Id.
Sterlingov did not make
this argument below, and as such, we review for plain error.
United States v. Bostick,
791 F.3d 127, 144
(D.C. Cir. 2015).
But Sterlingov has done little to show that the District Court
erred in its instruction, let alone that it plainly did so. He
provides slim reasoning for his argument, including no
pertinent authority or explanation for why the District Court’s
instructions were unlawful. 1 Consequently, we hold that venue
is proper in D.C. for Count I. 2

1
  We note that Sterlingov’s objection to the District Court’s venue
instruction is based solely on the government’s failure to allege in
Count One that Agent Price’s transaction occurred in the District.
See Appellant Br. at 23 (arguing that the District Court “allowed the
jury to find venue on Count One via conduct only alleged in Count
Two”). Sterlingov does not challenge the instruction on the basis
that it suggested a government agent’s actions can alone establish
venue for conspiracy charges. We therefore do not pass on that
question, which—had it been properly before us—would still require
Sterlingov to show that any error “affected the appellant’s substantial
rights.” Bostick,
791 F.3d at 144
.
2
  As explained in the preceding paragraphs, venue for Counts I and
II are proper based predominately on Agent Price’s engagement with
Bitcoin Fog from his office in D.C. Concurrent with his broader
venue arguments, Sterlingov raises that “[a]llowing venue to rest
solely on the Government’s single, unrequited message and the
mixing of licit Bitcoin would allow prosecutors to fabricate venue in
any district at will[.]” Appellant Br. at 25. While this Court has left
the possibility of “venue entrapment” open, we have reasoned that
the only way that such a thing could occur is if the “prosecution,
                                   11

            3. Counts III and IV – Unlicensed Money
                           Transmission

     Count III of the indictment charged Sterlingov with
operating an unlicensed money transmitting business under
18
U.S.C. § 1960
(a). The statute prescribes criminal liability for
whoever “knowingly conducts, controls, manages, supervises,
directs, or owns all or part of an unlicensed money transmitting
business.”
18 U.S.C. § 1960
(a). As relevant here, “unlicensed
money transmitting business” includes a business that is
“operated without an appropriate money transmitting license
in a State where such operation is punishable.”
Id.
§1960(b)(1)(A). “Money transmitting” includes “transferring
funds on behalf of the public by any and all means[,]
including . . . transfers . . . by wire.” Id. § 1960(b)(2).

     Similarly, Count IV of the indictment charged Sterlingov
with violating
D.C. Code § 26-1023
(c), the local analog to the
federal crime under
18 U.S.C. § 1960
(a). Like its federal
counterpart, the D.C. Code also imposes criminal liability on
anyone who conducts a money transmission business without
a license, where “[m]oney transmission” means the “sale or
issuance of payment instruments or engaging in the business of
receiving money for transmission or transmitting money within

preferring trial elsewhere, lure[d] a defendant to a distant district for
some minor event simply to establish venue.” United States v.
Sitzmann,
893 F.3d 811, 823
(D.C. Cir. 2018) (per curiam) (quoting
United States v. Spriggs,
102 F.3d 1245, 1251
(D.C. Cir. 1996), as
amend. (Feb. 20, 1997)). Regardless of whether “manufactured
venue” is a valid theory, it is clear that here, Bitcoin Fog operated
worldwide and without regard to the location of its users and thus
was not “lured” to D.C. by Agent Price. Accordingly, we find there
is no viable claim of “venue entrapment.”
                                 12
the United States, or to locations abroad, by any and all means,”
including “wire . . . or electronic transfer.”
D.C. Code § 26
-
1001(10). Both 18 U.S.C § 1960(a) and
D.C. Code § 26
-
1023(c) do not have any specific venue requirements.
Accordingly, we look to where the “conduct constituting the
offense” occurred to determine where venue may be properly
invoked. United States v. Rodriguez-Moreno,
526 U.S. 275,
279
(1999); FED. R. CRIM. P. 18.

     Sterlingov contends that for both Counts, venue is
improper in D.C. because he engaged in no “business conduct”
in the District, nor any business “operat[ion].” Appellant Br.
at 25–27. The government disagrees, arguing that venue is
proper in D.C. because the jury reasonably could have found
that Bitcoin Fog served customers in the District. Sterlingov
concedes that such conduct would be sufficient, Appellant Br.
at 26, and we conclude that the government introduced
sufficient evidence for a jury to find that Bitcoin Fog served
customers in D.C.         The evidence presented at trial,
predominately Agent Price’s sting operation, demonstrated that
Bitcoin Fog was receiving funds from and issuing funds to a
person in D.C. Additional evidence also established that D.C.
law required a money transmitting business to obtain a license
from the D.C. government, but that neither Bitcoin Fog nor
Sterlingov had obtained such a license. Because this is a crime
of failure to do a “legally required act, the place fixed for its
performance fixes the situs of the crime.” Johnston v. United
States,
351 U.S. 215, 220
(1956). In other words, venue for
Counts III and IV is thus proper in D.C. 3

3
  There is some question of whether liability under the D.C. provision
required Bitcoin Fog to have a physical operational presence in D.C.
See     Appellant Br. at          27 (suggesting         that   “[t]he
statute . . . contemplates an entity actively operating a money-
transmitting business within the District”). But this question was not
squarely presented to us by Sterlingov, and we decline to reach it.
                                 13

                      B. Statute of Limitations

     Sterlingov next asserts that there was “insufficient
evidence to establish criminal conduct” within the statute of
limitations for each of the Counts. Appellant Br. at 97. We
review such preserved claims de novo, see United States ex. rel.
Miller v. Bill Harbert Int’l Constr., Inc.,
608 F.3d 871, 878
(D.C. Cir. 2010), taking the facts in the light most favorable to
the jury’s verdict, and now affirm the District Court’s rejection
of Sterlingov’s claims.

     Each of the alleged violations had a limitations period of
five years, apart from Count IV, which had a limit of six years.
Sterlingov was indicted on Counts II, III, and IV on June 14,
2021, and indicted on Count I on July 18, 2022. This means
that the relevant offenses must have occurred on or after June
14, 2015, for Count IV, June 14, 2016, for Counts II and III,
and July 18, 2017, for Count I. The superseding indictment
alleged that the offense activity of Counts I, III, and IV all
began on or about October 27, 2011, and continued until at
least April 27, 2021.4 For Count II, the superseding indictment
alleged that the money laundering occurred on November 18,
2019.

     The crux of Sterlingov’s argument on appeal is that there
was “insufficient evidence to establish criminal conduct”
because “[a]lmost all the darknet markets in question were shut
down by the Government or ceased operations outside the
statute of limitations.” Appellant Br. at 97. It is true that

4
  Conspiracy and unlicensed money transmission are continuing
offenses, which means that the statute of limitations period begins to
run once the offenses cease. United States v. McGoff,
831 F.3d 1071
,
1078–79 (D.C. Cir. 1987).
                               14
darknet vendors like Silk Road, Nucleus, AlphaBay, Agora,
Nucleus, Abraxas, Pandora Openmarket, Sheep, and Black
Bank all shut down prior to 2017. But it is unclear what this
fact has to do with the statute of limitations period for the
substantive money laundering and licensing counts. Indeed,
Counts II, III, and IV are all grounded in Agent Price’s sting
transaction that occurred on November 21, 2019—evidence of
which would allow a reasonable jury to infer that as of that date,
Bitcoin Fog was still operating, and that money was being
laundered through the platform.

     The only rebuttal that Sterlingov gives to this is that the
government “offered no evidence that Sterlingov received or
read the messages accompanying the undercover transactions,”
Appellant Br. at 100, but as explained above in our analysis of
Sterlingov’s venue claims, the jury could reasonably conclude
otherwise. Because Agent Price’s transactions with Bitcoin
Fog happened within five and six years of the superseding
indictment, we reject Sterlingov’s challenges to the
government’s proof of compliance with the statutes of
limitations for these Counts.

     Sterlingov’s arguments regarding Count I fail for similar
reasons. It is true that many of the darknet market vendors that
the government discussed at trial had shutdown outside of the
statute of limitations period. See, e.g., App. 6411 (discussing
Silk Road, shut down in 2013), 6415 (discussing Sheep, shut
down in 2013). The final identified transaction between
Bitcoin Fog and one of the named darknet vendors, AlphaBay,
occurred on July 5, 2017, just 13 days shy of the limitations
period. App. 6412. But Count I is timely if the jury can infer
that the conspiracy continued with unknown co-conspirators
for at least two weeks following the final identified transaction
with a named darknet vendor. A plethora of circumstantial
evidence supported such an inference, including Agent Price’s
                               15
transactions with Bitcoin Fog in November 2019. Further, the
continued operation of Bitcoin Fog until Sterlingov’s arrest in
2021, and its continued profitability following the shutdown of
the last named darknet vendor, is sufficient circumstantial
evidence to allow the jury to infer that the conspiracy to money
launder continued with unknown co-conspirators within the
limitations period. Accordingly, Sterlingov’s statute of
limitations arguments fail.

                      C. Expert Testimony

     Sterlingov next contends that the District Court erred in
admitting the testimony of three experts: former FBI task force
officer Valerie Mazars de Mazarin, FBI agent Luke Scholl, and
Chainalysis Government Solutions (“Chainalysis”) analyst
Elizabeth Bisbee. Sterlingov’s main contention against the
admission of their expert testimony was that their testimony did
not satisfy “the reliability requirements of Fed. R. Evid. 702 or
Daubert.” Appellant Br. at 27. This Court reviews the decision
to admit expert testimony for abuse of discretion, granting the
“district court . . . broad latitude when it decides how to
determine reliability,” as well as in its “ultimate reliability
determination.” United States v. Morgan,
45 F.4th 192, 200
(D.C. Cir. 2022) (quoting Kumho Tire Co. v. Carmichael,
526
U.S. 137, 142
(1999)). We have considered Sterlingov’s
arguments regarding each expert and ultimately find none to be
persuasive.

     Federal Rule of Evidence 702 governs the testimony of a
witness who is “qualified as an expert by knowledge, skill
experience, training, or education” and outlines four factors
that must be met before such expert testimony can be admitted:
(1) the expert will “help the trier of fact to understand the
evidence or to determine a fact in issue”; (2) “the testimony is
based on sufficient facts or data”; (3) “the testimony is the
                                16
product of reliable principles and methods”; and (4) “the
expert’s opinion reflects a reliable application of the principles
and methods to the facts of the case.” FED. R. EVID. 702.

     The Supreme Court outlined certain considerations for the
Rule 702 inquiry in its seminal case Daubert v. Merrell Dow
Pharms., Inc.,
509 U.S. 579
(1993). These considerations
include whether the theory or technique the expert is testifying
about has been tested, whether it has been the subject of peer
review or publication, the known or potential rate of error for
the theory or technique, and finally, whether the theory or
technique is generally accepted.
Id.
at 593–94. Daubert
highlighted, however, that these considerations were not “a
definitive checklist,”
id. at 593
, and subsequent Supreme Court
precedent is clear that the “factors identified in Daubert may or
may not be pertinent in assessing reliability, depending on the
nature of the issue, the expert’s particular expertise, and the
subject of his testimony.” Kumho Tire,
526 U.S. at 150
(citation modified). Whether an expert’s testimony should be
admissible is thus a deeply fact intensive question, with much
“depend[ing] upon the particular circumstances of the
particular case at issue.” Id.

           1. Testimony of Valerie de Mazars Mazarin

     Keeping the above governing rules and principles in mind,
we begin by reviewing Sterlingov’s claim that the District
Court erred in admitting the expert testimony of Valerie de
Mazars Mazarin, a former FBI task force officer. Mazars
testified that, as part of her work in digital forensics, she would
often “analyz[e] web logs . . . [and] IP log-ins . . . searching for
patterns and key information,” and would “write and develop
tools to help review that type of evidence.” App. 1359; see also
App. 1374. An IP address is “an identifier that a computer
connected to the internet uses so that the rest of the internet can
                               17
find it.” App. 1363. When a user interacts with a website, the
website typically records the IP address associated with the
interaction. App. 1371–72. A user’s IP address is usually not
specific to the device used to interact with the website. Instead,
the user’s IP address for that interaction is based on how the
internet connection was made with the website, so the user’s IP
address for a specific interaction could be that of a home router,
of a proxy server, of a public WiFi network, of a Virtual Private
Network or of a Tor Network node, among others. See App.
4846–50.

      Specific to the investigation into Sterlingov, Mazars stated
that she had reviewed “account login records [provided by the
IRS to Mazars] for a number of different accounts tied to”
Sterlingov and Bitcoin Fog to conduct an “IP overlap analysis.”
App. 1391. She identified instances in “which the same IP
address was used to access multiple accounts,” and then filtered
that large data set to perform a “microanalysis” and focus on
“the connections that were closest in time.” App. 1375.
Mazars testified that she filtered the data set by applying time
cutoffs based on inferences about the universal time code
convention (Greenwich Mean Time) and then created overlap
windows, further explaining why she had chosen the specific
filters that she did. As a result of her analysis, Mazars
concluded that the same user “likely” accessed accounts
associated with both Sterlingov and Bitcoin Fog. App. 4624.
During cross-examination, Mazars admitted that it was her
“first time” using that specific methodology and that the
method that she had used was not peer reviewed as it was not a
“scientific construct” and could not be studied. App. 1404–05.

     Sterlingov latches on to these admissions by Mazars to
argue that her testimony is not reliable under Daubert.
Sterlingov’s contention is that because the government did not
put on evidence to demonstrate that the testimony was reliable
                                18
under all of the factors outlined in Daubert—i.e., that the IP
Overlap Analysis had been tested, was the subject of peer-
review, had a low error rate, and was “generally accepted”—
then the logical conclusion must be that the District Court
abused its discretion in admitting such testimony. However, as
we have explained, the factors outlined in Daubert are not the
sole basis for qualification as an expert and there is “[n]o
specific inquiry . . . demanded of the trial court.” United States
v. Straker,
800 F.3d 570, 631
(D.C. Cir. 2015) (per curiam).
While it is true that Mazars did not present evidence that the
technique that she used was widely accepted or had a low error
rate, she did present ample testimony explaining her
methodology, including why she had selected different overlap
windows and made certain inferences about the time stamps
within the IRS-provided sheets. She also explained that she
had experience in reviewing and analyzing IP log-ins and
patterns, and that while it was the first time that she had
conducted “that specific methodology,” see App. 1404, she
would often analyze IP logins for patterns, App. 1359. In this
way, Mazars’s testimony was “grounded in an accepted body
of learning or experience in the expert’s field.” See FED. R.
EVID. 702 advisory committee’s note to 2000 amendment.
Further, the District Court permitted Sterlingov to probe the
basis and reliability of Mazars’s methodology with “[v]igorous
cross-examination.” Daubert,
509 U.S. at 596
. Accordingly,
the District Court did not abuse its discretion in admitting
Mazars’s testimony regarding the IP Overlap Analysis. 5




5
   Sterlingov challenges Mazars’s testimony and methodology
generally, and not specifically whether Mazars’s conclusion that the
same user “likely” accessed accounts associated with Sterlingov and
Bitcoin Fog was unsupported expert testimony. We decline to decide
that question here.
                               19
       2. Testimony of Luke Scholl and Elizabeth Bisbee

     The same conclusion arises for Sterlingov’s other Daubert
claims, which relate to government experts Scholl and Bisbee.
Both individuals testified regarding “Reactor,” a Chainalysis
tool used to trace cryptocurrency transactions by “clustering”
bitcoin addresses to a single entity. United States v. Sterlingov,
719 F. Supp. 3d 65
, 68 (D.D.C. 2024). Both experts testified
that they used this technology to examine the transactions
between Bitcoin Fog and a variety of darknet markets, App.
564, 610, ultimately testifying that Reactor had “clustered and
attributed” to Bitcoin Fog over 900,000 Bitcoin addresses, with
eight darknet markets sending approximately 80,000 bitcoin to
the mixer. See, e.g., App. 6956. Sterlingov contends that both
witnesses’ testimony is unreliable under Federal Rules of
Evidence 702 because it was not peer-reviewed or
independently tested and completely lacked “any known error
rates, false positive rates or false negative rates”—all of which,
he argues, demonstrate that the Reactor evidence and related
expert testimony failed to meet the Daubert standards. See
Appellant Br. at 31.

      Prior to delving into whether the testimonies were reliable,
it is necessary to first understand what Reactor is and how it
operates, as well as reiterate how blockchain functions. As
deftly explained by the District Court in this case,
cryptocurrency transactions are recorded on the blockchain,
with both sending addresses and receiving addresses being
public. It is also possible for one person—or one virtual
wallet—to hold multiple addresses. Those addresses can
contain different amounts of bitcoin and can be leveraged for
purchases, with all the addresses requiring a private key for any
transaction. So, for example, Person A may have one wallet
with three bitcoin addresses, but the first bitcoin address may
only have 3 bitcoin, the second only 2, and the third only 1. If
                               20
Person A desires to purchase a good from Person B with their
bitcoin, but that good costs 5.5 bitcoin, Person A would need
to transfer the bitcoin from all three of their addresses in order
to fund the transaction. In conducting such a transaction,
Person A’s identity would be anonymous, but the fact that three
addresses simultaneously sent bitcoin to an anonymized Person
B would not be. One can imagine, then, that if you could
“cluster” the three addresses together based on certain
parameters, you could trace the entirety of the transaction back
to Person A, and then identify Person A through additional
means. See generally Sterlingov, 719 F. Supp. 3d at 71–74.

     Note as well that in the example above, Person A would
be giving Person B an additional 0.5 bitcoin, which is returned
as change. This is a requirement of the way cryptocurrency
works. Person A cannot “break up” the 1 bitcoin in their third
wallet the same way that one cannot obtain change for a $20
bill on a $10 purchase by merely ripping up the $20 bill. App.
606–07. For that 0.5 bitcoin of change, the wallet software will
generate a new “change” address, meaning that instead of three
addresses in one wallet, Person A now has four addresses in
one wallet—three addresses have no bitcoin within them, and
one address has 0.5 bitcoin. App. 607; see also Sterlingov, 719
F. Supp. 3d at 74. This is known as the “change address
analysis.” Id.

     All of these principles are essential to understanding how
Reactor works. As Bisbee testified, the clustering done by
Reactor depends on three separate heuristics. The first is
known as the “co-spend” heuristic, which assumes that a single
person or entity controls a group of input addresses used
together in a single transaction. App. 605, 610. Put in terms
of the example used above, the co-spend heuristic facilitates
the assumption that only one person—Person A—controls a
common set of sending or receiving addresses. The second
                               21
heuristic is known as the “behavioral heuristic,” which is “the
behavior of how the transactions are occurring on the
blockchain.”      App. 606.        Reactor uses a proprietary
algorithm—the underlying factors which can include the
change address analysis discussed above, as well as the “digital
fingerprint that is left behind” “every time a transaction occurs
on the blockchain”—to cluster addresses that engage in
transactions matching certain behavioral patterns. Id.; Gov’t
Br. at 37. The third heuristic is “intelligence-based clustering,”
which uses information obtained from data leaks, court
documents, and data partnerships to further determine
connections between addresses and entities. App. 608. Using
each heuristic individually, or through a combination of the
heuristics, Reactor is able to “cluster” sending and receiving
addresses together to ultimately demonstrate the magnitude of
transactions involving Bitcoin Fog and various darknet sites.

     Both experts admitted that Reactor was not peer-reviewed
and that they did not know the error rate for the software. App.
622–23, 4142–43. Sterlingov claims that this definitively
demonstrates that Scholl and Bisbee’s expert testimony was
unreliable under Daubert. But again, the Daubert factors are
not exhaustive. See Kumho Tire,
526 U.S. at 150
. And the
experts’ testimony provided other markers of reliability.

     One such marker was anecdotal evidence. Scholl testified
that he could not recall a time where he “reviewed a subpoena
where [Reactor] attribution wasn’t correct,” App. 4137, and
Bisbee testified similarly, noting that she could not recall a
time, over the process of thousands of reviews, where Reactor
“said something was clustered in a way that was not correct.”
App. 638–39. Sterlingov asserts that the District Court erred
in accepting such testimony as proof of Reactor’s reliability
because “anecdotal case reports are universally regarded as an
insufficient scientific basis for a conclusion.” Appellant Br. at
                              22
35 (citation modified). To support his proposition, Sterlingov
cites a slew of Eleventh Circuit cases. Those cases are
inapposite. They hold that anecdotal experiences cannot rebut
“controlled, population-based . . . studies.” Allison v. McGhan
Med. Corp.,
184 F.3d 1300
, 1316 (11th Cir. 1999); see also
McClain v. Metabolife Int’l Inc.,
401 F.3d 1233, 1250
(11th
Cir. 2005) (similar). Scholl and Bisbee did not offer anecdotal
evidence to rebut any controlled studies—instead, their
anecdotal evidence actually included discussion of Reactor
outputs in controlled environments, such as comparing clusters
and attributions to later legal processes. This was a proper use
of anecdotal evidence.

     Another marker of reliability was Scholl and Bisbee’s
testimony that Reactor was an industry standard tool that was
largely used by law enforcement and private-sector specialists.
See Sterlingov, 719 F. Supp. 3d at 84. This “general
acceptance” of the tool “can be an important factor in ruling
particular evidence admissible.” See Daubert,
509 U.S. at 594
.
While Sterlingov doesn’t disagree that “general acceptance” is
a factor espoused in Daubert for determining reliability, he
asserts that “market acceptance” cannot be “scientific
acceptance.” Appellant Br. at 45–46 (emphasis omitted). This
is incorrect. This Court has found that both law enforcement
and industry usage is an acceptable proxy for determining the
general acceptance of a technology in a community. Morgan,
45 F.4th at 202
; see also United States v. Gissantaner,
990 F.3d
457, 468
(6th Cir. 2021) (explaining that just because a
technology has been developed for a for-profit entity, “that
would not belittle [the technology’s] reliability”). The general
acceptance of Reactor then becomes another factor that weighs
in favor of its reliability.

    And there were other markers of reliability still. Other
sources also corroborated Reactor’s clustering, with one
                                  23
government contractor confirming that Reactor had correctly
clustered and attributed 99.9% of a large number of addresses
in a different case. S.A. 283. Scholl testified that he had
searched Reactor’s Bitcoin Fog cluster for the five addresses
that Bitcoin Fog used during the government’s undercover
transactions. App. 561–62. He found that Reactor had
properly identified four of them as associated with Bitcoin
Fog. 6 App. 560–63. And Scholl and Bisbee’s in-depth
testimony explaining how Reactor worked and the underlying
assumptions that it made further went to establishing its
reliability, as the tool itself was based on reliable principles and
methods. Accordingly, we hold that the District Court did not
abuse its discretion in admitting the testimony of Scholl and
Bisbee. 7

                D. Denial of Access to Source Code

    Sterlingov next challenges the District Court’s decision to
deny him access to Reactor’s source code. As explained above,
Scholl and Bisbee’s expert testimony relied in part on Reactor,

6
 Sterlingov views Reactor’s success rate as a negative here, claiming
that Scholl’s manual test rendered a 20% error rate. But, as the
District Court found, Reactor is “deliberatively conservative and thus
underinclusive,” and for the purposes of this case, that can “hardly
[be a] reason to discount its reliability.” Sterlingov, 719 F. Supp. 3d
at 79.
7
  It is true, as Sterlingov asserts, that Reactor was not peer-reviewed.
But “it might not be surprising in a particular case . . . that a claim
made by a scientific witness has never been the subject of peer
review,” especially when that technology is “too new, or of too
limited outside interest[] to generate extensive independent research
or peer-reviewed publications.” Morgan,
45 F.4th at 203
(citations
omitted). Blockchain tracing certainly falls within this bucket.
                              24
a proprietary software product that clusters bitcoin addresses
using three heuristics. Sterlingov requested Reactor’s source
code in the proceeding below, to which the District Court
responded that Sterlingov first needed to explain why his
access to the code was “material and relevant in the criminal
case” before it could grant him access. App. 375–76. Despite
numerous follow-ups from the Court, Sterlingov never
provided any explanation.

     Rather than presenting his reasoning for needing access to
Reactor’s source code, Sterlingov filed a motion for leave to
issue a Rule 17(c) subpoena that would require Chainalysis, the
owner of Reactor, to produce its source code. After a hearing,
the District Court ordered Chainalysis to submit the heuristics
and assumptions underlying Reactor (hereinafter “Reactor
Discovery”) to Sterlingov’s counsel under a protective order
but refrained from making any decisions about Reactor’s
source code. The District Court also exercised its discretion
under Federal Rule of Criminal Procedure 16(d)(1) to restrict
Sterlingov from personally reviewing the Reactor Discovery,
but allowed Sterlingov’s counsel, and any qualified experts, to
view the material. The District Court reasoned that because the
Reactor Discovery included the assumptions the tool used to
“cluster,” the discovery could potentially provide a road-map
to those wanting to elude law enforcement for circumventing
bitcoin tracing technologies. Since Sterlingov was alleged to
be the administrator of Bitcoin Fog, which was further alleged
to have been “designed and employed to help bitcoin users
avoid clustering and tracing of their on-chain activities,” the
District Court found that it had good cause under Rule 16(d)(1)
to restrict Sterlingov’s access to the Reactor Discovery.
Sterlingov,
704 F. Supp. 3d 176
, 180 (2023).

    Sterlingov later again asked for the source code in a
discovery request. The District Court ultimately denied
                                  25
Sterlingov’s motion for leave to issue a Rule 17(c) subpoena
for that source code. The District Court ruled that Sterlingov
had not shown that he needed the source code, especially in
light of his counsel’s access to Reactor’s heuristics and
underlying assumptions. Sterlingov now argues that such a
denial was a violation of his Confrontation Clause rights under
the Sixth Amendment and his Due Process rights under the
Fifth Amendment.

                       1. Confrontation Clause

     Sterlingov argues that the District Court violated his
Confrontation Clause rights when it denied him access to
Reactor’s source code. Sterlingov acknowledges that “some of
the heuristics behind [Reactor’s] conclusions were disclosed to
Defense counsel in limited fashion,” but asserts the
“information was of limited use.” Appellant Br. at 51. Because
Sterlingov did not raise these constitutional objections below,
“our review is for plain error.” Bostick,
791 F.3d at 149
. 8

     The Sixth Amendment’s Confrontation Clause provides
that “[i]n all criminal prosecutions, the accused shall enjoy the
right to . . . be confronted with the witnesses against him[.]”
U.S. CONST. amend. VI. The Supreme Court has interpreted
this constitutional provision to mean that “[w]here testimonial

8
 Sterlingov did raise below that the District Court’s decision to deny
him access to the heuristics that underlie Reactor’s attributions and
outputs (as opposed to his counsel) was a violation of the Fifth and
Sixth Amendments. That claim would be reviewed de novo on
appeal. Straker,
800 F.3d at 629
. However, the claims that
Sterlingov asserts on appeal are different, as he now argues that the
denial of “full access to Reactor” (including the source code) violated
his constitutional rights. Appellant Br. at 51. Regardless of the
standard of review that we apply, however, Sterlingov’s
Confrontation Clause and Due Process claims are still unpersuasive.
                              26
statements are at issue,” the government may not offer into
evidence such a statement without the witness who said it
unless that witness is unavailable and the defendant had a prior
opportunity for cross examination. Crawford v. Washington,
541 U.S. 36
, 68–69 (2004). Statements are “testimonial,” in
turn, if they were made with the primary “purpose of
establishing or proving some fact,” Melendez-Diaz v.
Massachusetts,
557 U.S. 305, 310
(2009) (citation modified),
or with the specific “purpose of creating an out-of-court
substitute for trial testimony,” Ohio v. Clark,
576 U.S. 237
,
250–51 (2015) (citation modified). Sterlingov asserts that
“[t]he attribution outputs of Reactor, which are made in aid of
government investigations, . . . rank as testimonial,” and that
“denying confrontation for machine-generated evidence, like
Reactor’s clustering attributions” “resembles trial by ex parte
affidavit.” Appellant Br. at 52–53 (citation modified).

     Sterlingov’s own concession that Reactor’s attributions
are “machine-generated” doom his case. Our sister Circuits
have recognized that machine-generated outputs are not
hearsay statements, nor are they testimonial for Confrontation
Clause purposes. United States v. Miller,
982 F.3d 412, 437
(6th Cir. 2020) (describing the “text and history” of the
Confrontation Clause to conclude that it “encompasses
statements by people, not information by machines”); United
States v. Lizarraga-Tirado,
789 F.3d 1107, 1110
(9th Cir.
2015) (holding that a tack indicating a particular location on
Google Maps would only be a person’s “assertion”—and thus
hearsay—if it was manually placed, instead of automatically
inserted, and further holding that “machine statements aren’t
hearsay”); United States v. Lamons,
532 F.3d 1251
, 1262–64
(11th Cir. 2008) (holding that “machine-generated statements”
are not implicated by the Confrontation Clause because “the
witnesses with whom the Confrontation Clause is concerned
with are human witnesses” (emphasis in original)). And at
                              27
least some members of the Supreme Court have suggested that
“machine-generated” results may not implicate the
Confrontation Clause. See Bullcoming v. New Mexico,
564
U.S. 647
, 673–74 (2011) (Sotomayor, J., concurring in part)
(noting that the results of Bullcoming may have been different
had it involved “machine-generated results” and that the case
was not opining on whether the “[s]tate could
introduce . . . raw data generated by a machine in conjunction
with the testimony of an expert witness”); Smith v. Arizona,
602 U.S. 779, 804
(2024) (Thomas, J., concurring) (“I continue
to adhere to my view that the Confrontation Clause is
implicated by extrajudicial statements only insofar as they are
contained in formalized testimonial materials, such as
affidavits, depositions, prior testimony, or confessions.”
(citation modified)).

     Sterlingov has given us no reason to conclude that
machine-generated evidence in this case is somehow different
and requires departure from the holdings of the other Circuits.
His best argument is that because Reactor is programmed by
humans, who make “judgments [regarding] how to encode the
heuristics, what intelligence and data existing outside the
blockchain to include, and how to give weight to that off-chain
data,” Reactor’s attributions are “an inference drawn from a
proprietary, human-designed model,” not just data that was
automatically generated by a machine. Appellant Br. at 53–54.
But even if we were to accept that as true, Sterlingov’s
Confrontation Clause rights would, at most, be invoked against
Reactor’s programmers—the Sixth Amendment would not
require Chainalysis to give up Reactor’s source code, at least
not as the facts are presented here. But see Miller, 982 F.3d at
437–38 (holding that the Supreme Court’s decision in
Melendez-Diaz “disclaimed any broader notion that the
Confrontation Clause reached everyone whose testimony may
be relevant in establishing the . . . accuracy of the testing
                                 28
device used in a case” (citation modified)). Because Sterlingov
has not demonstrated that the District Court plainly erred and
violated his Sixth Amendment rights in denying him access to
Reactor’s source code, his Confrontation Clause claim fails. 9

                            2. Due Process

     Sterlingov next alleges that the denial of access to
Reactor’s source code violated his Fifth Amendment Due
Process right to put on a complete defense because “the
underlying inputs behind Reactor’s clustering and attribution
conclusions are exculpatory.” Appellant Br. at 59. However,
at no point in his opening brief does Sterlingov contest the
District Court’s denial of his requests for Rule 17(c) subpoenas,
which Sterlingov filed partly for the purpose of obtaining
Reactor’s source code. Because Sterlingov failed to raise this
claim in his opening brief, he has forfeited any argument
challenging the District Court’s denial of his motion for leave
to issue a Rule 17(c) subpoena, and any due process claims
bound up in that denial. NetworkIP, LLC v. FCC,
548 F.3d
116
, 128 n.10 (D.C. Cir. 2014); see Al-Tamimi v. Adelson,
916
F.3d 1, 6
(D.C. Cir. 2019) (“A party forfeits an argument by
failing to raise it in his opening brief.”).

     Even if we construe Sterlingov as somehow raising an
independent due process claim regarding the District Court’s
refusal to grant him access to Reactor’s source code, such a
claim would still fail. This is because Sterlingov has never

9
  Sterlingov also briefly raises that the protective order under which
the District Court allowed the disclosure of the Reactor Discovery
contained a “draconian” non-compete provision, which caused trial
defense counsel and defense experts to refrain from signing.
Appellant Br. at 43–44. However, Sterlingov’s experts stated below
that they refused to review the Reactor discovery disclosures
“regardless of the scope of any protective order.” App. 6884.
                               29
expressed, either to us or to the District Court below, why the
source code, by itself, is important to his defense. The District
Court displayed a willingness to provide the source code to the
defense on numerous occasions, see, e.g., App. 1494-95, but
was stonewalled by Sterlingov’s own refusal to explain why
the code was “material and relevant in the criminal case.” App.
375–76. Such silence is even more telling when considering
that Sterlingov’s counsel was given access to the heuristics and
other underlying assumptions for Reactor.            Ultimately,
Sterlingov “has failed to demonstrate any material impairment
of his defense.” Straker,
800 F.3d at 630
.

                             ***

     Sterlingov also argues that the District Court’s invocation
of Rule 16(d)(1) to restrict his personal access to the Reactor
Discovery was a violation of his Due Process and
Confrontation Clause rights. Sterlingov asserts that the District
Court’s reasoning for restricting Sterlingov’s personal access
to the discovery—which was grounded in the fact that
Sterlingov was alleged to be the creator of a platform designed
to evade enforcement of illegal activities—was an “improper
assumption of guilt, as well as an assumption of future criminal
activity.”    Appellant Br. at 57.        Notwithstanding the
presumption of innocence, the indictment and surrounding
circumstances provided good cause for the District Court to
take appropriate action to mitigate the risks of disclosing
sensitive information directly to Sterlingov. Therefore, the
District Court did not plainly err in restricting Sterlingov’s
access to certain discovery, and there was no Due Process or
Confrontation Clause violation in such an action.
                               30
         E. Admission of Welcome to Video Evidence

      Sterlingov next contests the District Court’s admission of
something he calls “Welcome to Video” evidence, arguing that
such admission was a violation of Federal Rule of Evidence
403, which allows a district court to “exclude relevant evidence
if its probative value is substantially outweighed by a danger of
… unfair prejudice.” FED. R. EVID. 403. The rule “tilts . . .
toward the admission of evidence in close cases,” with the trial
court being in the “best position to perform this subjective
balancing.” United States v. Cassell,
292 F.3d 788
, 795–96
(D.C. Cir. 2002) (citation modified). Accordingly, this Court
reviews the District Court’s application of Rule 403 for abuse
of discretion. Morgan,
45 F.4th at 204
.

      Welcome to Video was a darknet site that allowed users to
purchase child sexual abuse material. The government
introduced evidence at trial that demonstrated that users of
Bitcoin Fog were sending funds to this darknet site, arguing
that the evidence was relevant because it showed the type of
“activity that Bitcoin Fog is facilitating.” App. 4090. The
evidence was presented via spreadsheet. Sterlingov objected
to its admittance, arguing that it would be more prejudicial than
probative. The District Court eventually allowed the evidence
in, after the government agreed to redact the names of the child
pornography videos.

     Sterlingov does not appear to contest that the evidence had
some relevance to the unlicensed money transmitting charge
under
18 U.S.C. § 1960
. But he argues that because there was
already other evidence that demonstrated that “users mixed
criminal proceeds through Bitcoin Fog,” the evidence had
“marginal[] probative” value. Appellant Br. at 62–63. Maybe
so. But the “government is, in general, permitted to determine
how to present its case,” and is not “limited to one piece of
                                 31
evidence for each material fact.” United States v. Curtis,
481
F.3d 836, 838
(D.C. Cir. 2007). The evidence had probative
value because it presented further evidence of the wrongful
conduct that was occurring through Bitcoin Fog’s platform.
And this probative value was not “substantially outweighed by
a danger of” unfair prejudice because the most prejudicial
information within the evidence—the names of the videos—
was redacted before being presented to the jury. FED. R. EVID.
403 (emphasis added). 10 Accordingly, the District Court did
not abuse its discretion when it admitted the Welcome to Video
evidence.

         F. Constructive Amendment of the Indictment

     Flowing from the admission of the Welcome to Video
evidence, Sterlingov also briefly argues that the government’s
“reliance on the Welcome to Video evidence amounted to a
constructive amendment of the indictment, infringing
Sterlingov’s Fifth Amendment right to be tried only on charges
returned by the grand jury.” Appellant Br. at 68; see also
United States v. Riley,
115 F.4th 604, 615
(D.C. Cir. 2024)
(explaining that constructive amendment is unlawful because
it “deprives the defendant of the right to be tried upon the
charge in the indictment as found by the grand jury” (citation
modified)). Sterlingov further asserted that because Count I of
the indictment only alleged conspiracy with darknet drug

10
   Sterlingov claims that the prejudice was elevated in his case
because the District Court never issued a limiting instruction to the
jury. Additionally, because no limiting instruction was given,
Sterlingov asserts that this Court could not possibly hold that any
error in admitting the evidence was harmless. But Sterlingov never
asked for a limiting instruction. “[A] tactical decision by defense
counsel not to seek a limiting instruction—and a district court’s
resultant failure to give one—does not preclude finding harmless
error.” United States v. Green,
149 F.4th 733
, 757 (D.C. Cir. 2025).
                               32
vendors, rather than with “patrons of a child-pornography site,”
admitting the Welcome to Video evidence without any limiting
instruction thus broadened the scope of Count I, ultimately
allowing the jury to find Sterlingov guilty of the Count if they
found that Sterlingov engaged in a conspiracy with customers
of darknet vendors. Appellant Br. at 68–69. Because
Sterlingov did not raise this challenge below, this Court
reviews only for plain error. Riley,
115 F.4th at 615
.

     We find no plain error. To determine whether admitted
evidence constructively amended an indictment, Sterlingov
must demonstrate that the “evidence presented at trial and the
instructions given to the jury so modified the elements of the
offense charged that the defendant may have been convicted on
a ground not alleged by the grand jury’s indictment.”
Id. at 615
(citation modified). Sterlingov fails to explain how the
instructions given to the jury modified the elements of the
offense charged. In fact, the jury instructions actually
precluded the jury from finding Sterlingov guilty of conspiracy
based on the theory that Sterlingov conspired to launder money
with customers of child pornography sites because it made
clear that the only way to find guilt was to find that Sterlingov
acted with the intent to carry out the specified unlawful activity
of “dealing in a controlled substance.”              App. 6272.
Accordingly, we hold that the introduction and admittance of
the Welcome to Video evidence did not constructively amend
the indictment.

            G. Testimony of Cooperating Witnesses

     During the course of trial, the government introduced the
testimony of two cooperating witnesses, Ilya Lichtenstein and
Larry Harmon. Both Lichtenstein and Harmon disclaimed
knowing Sterlingov, but they testified to using Bitcoin Fog a
handful of times each to launder illicitly procured money.
                               33
Both witnesses also disclosed that they had pled guilty to
money-laundering conspiracy charges unrelated to Sterlingov,
and Harmon additionally disclosed pleading guilty to two
additional licensing charges. Sterlingov asserts that the
testimony of these cooperating witnesses was irrelevant
(presumably under Rule 401), unfairly prejudicial under Rule
403, and improper expert testimony in violation of Rule 702.
The District Court admitted both witnesses’ testimony over the
objection of Sterlingov. We review for abuse of discretion, see
United States v. Clark,
156 F.4th 664
, 687–88 (D.C. Cir. 2025),
and ultimately find none here.

     As an initial matter, Sterlingov provides no reasoning in
his papers as to why the testimony of Lichtenstein and Harmon
was irrelevant, prejudicial, or improper. In failing to properly
flesh out his arguments, Sterlingov has forfeited them. Al-
Tamimi,
916 F.3d at 6
. But even if we were to reach the merits,
the District Court did not abuse its discretion. The testimony
of the witnesses was clearly relevant to illustrating for the jury
how Bitcoin Fog could be used for illegal purposes. See United
States v. Green,
149 F.4th 733
, 755 (D.C. Cir. 2025)
(“Ultimately, the bar for relevance is low[.]”). The potential
prejudice was limited given that neither witness knew
Sterlingov, and they were not testifying about crimes related to
the defendant. And both witnesses spoke only about their own
criminal enterprises, offering testimony that is suited for lay
opinion testimony. See FED. R. EVID. 701 (noting that lay
opinion testimony is one that is “rationally based on the
witness’s perception” and is not “scientific, technical” or
otherwise specialized in nature). Thus, Sterlingov’s claims
regarding these cooperating witnesses all fail.
                                 34
                  H. Willful Blindness Instruction

     After the close of trial, the District Court, over defense
objection, gave a willful blindness instruction to the jury. The
instruction informed the jury that they could find that
Sterlingov “had knowledge of a fact” if they found that
Sterlingov “deliberately closed his eyes to what would
otherwise have been obvious to him.” App. 6265. The District
Court further instructed that knowledge could not be
established “merely by demonstrating [Sterlingov] was
negligent, reckless, careless, or foolish[,]” but could be inferred
if Sterlingov had “deliberately blinded himself to the existence
of a fact he believed to a high probability of a certainty
existed.” Id.; see also S.A. 89. Sterlingov contends that the
District Court erred in providing such an instruction. 11 We
disagree.

     Our Circuit has previously held that the willful blindness
instruction should be given only in “rare circumstances” and
that the district court should be “wary” of such an instruction.
United States v. Alston-Graves,
435 F.3d 331, 341
(D.C. Cir.
2006) (citation modified). We need not define those rare
circumstances today, however, because the parties before us
agree that a willful blindness instruction is appropriate “when
[1] a defendant claims a lack of guilty knowledge and [2] the
proof at trial supports an inference of deliberate ignorance.”
Appellant Br. at 71-72 (quoting United States v. Lee,
966 F.3d
310, 324
(5th Cir. 2020)); Appellee Br. 87 (same).

11
   Generally, when the propriety of submitted jury instructions is
called into question, we review de novo. Clark, 156 F.4th at 664.
However, both parties agree that in this context, where the contention
is whether the evidence submitted supports a particular instruction,
abuse of discretion is the proper standard. See United States v.
Heredia,
483 F.3d 913, 922
(9th Cir. 2007). Accordingly, we have
applied the abuse of discretion standard here.
                               35

     Applying the parties’ shared test, we conclude that the
willful blindness jury instruction was validly given. Sterlingov
asserts that he “never claimed ignorance that Bitcoin Fog
served as a mixer for illicit criminal proceeds,” because his
defense was centered on the argument that Sterlingov was not
involved in Bitcoin Fog at all. Appellant Br. at 72. But that is
not the entire picture. As described earlier, Sterlingov
contested his guilty knowledge by arguing that the government
had not proved he had seen Agent Price’s messages about why
he was using Bitcoin Fog. Thus, at least some aspect of
Sterlingov’s defense was that he lacked any guilty knowledge
of the kind of illicit behavior that Bitcoin Fog was facilitating.
Therefore, the first prong of the parties’ willful blindness test
is fulfilled.

     The District Court also did not abuse its discretion in
finding that the second prong of the parties’ test was fulfilled.
There were numerous pieces of evidence demonstrating that
Sterlingov took deliberate steps to avoid learning of the illicit
conduct that was facilitated by Bitcoin Fog. Many of these
steps involved Bitcoin Fog’s architecture, which was
specifically designed to anonymize the transactions and
transactors. The platform auto-deleted its records every week.
A reasonable jury could infer that Sterlingov intentionally
designed the system this way so that he would have limited
access to user information and what users were doing with their
bitcoin. Additionally, Bitcoin Fog, unlike other bitcoin
services, didn’t have an account-verification process and asked
zero questions of users. A reasonable jury could infer that
Bitcoin Fog was run this way so that Sterlingov could avoid
any suggestion that he knew users of Bitcoin Fog were utilizing
it for criminal means. See United States v. Flores,
454 F.3d
149, 156
(3d Cir. 2006). Taking the evidence together, the
District Court did not abuse its discretion in finding that the
                              36
evidence raised an inference that Sterlingov had
metaphorically stuck his head into the sand. Accordingly, we
reject Sterlingov’s willful blindness claim.

        I. Alleged Miscalculation of Laundered Funds

    Finally, Sterlingov contests the District Court’s
calculation of the laundered funds. For the reasons enumerated
below, this claim also fails.

      In calculating Sterlingov’s advisory range under the
Sentencing Guidelines, the District Court used only the money-
laundering conspiracy count to determine Sterlingov’s offense
level. Sterlingov takes no issue with that, but he nonetheless
asserts that the District Court wrongly calculated the amount of
illegally laundered funds, which unlawfully inflated his offense
level.

     U.S.S.G. § 2S1.1(a)(2) governs the calculation of the
offense level for money-laundering conspiracy, and it provides
that when a case involves a transaction which includes the
commingling of both “legitimately derived funds with
criminally derived funds,” it is only the “criminally derived
funds” that should be counted as the “value of the laundered
funds” if the defendant “provides sufficient information to
determine the amount of criminally derived funds without
unduly complicating or prolonging the sentencing process.” Id.
§ 2S1.1 cmt. n.3(B). Otherwise, if the “amount of the
criminally derived funds is difficult or impracticable to
determine”—in other words, if it is impracticable to detangle
the licit funds from the illicit funds—then the “value of the
laundered funds . . . is the total amount of the commingled
funds.” Id. Below, the government argued that the total value
of the laundered funds was all the money funneled through
Bitcoin Fog, totaling approximately $400 million and resulting
                                37
in a 28-level enhancement, while Sterlingov argued that the
value could be no greater than approximately $78 million,
resulting in a 22-level enhancement. The District Court
adopted the government’s view, explaining that the reasonable
inference is that “whoever was running the darknet sites was
engaging in some hops to further obscure themselves.” S.A.
347, 350.

     Sterlingov asserts that the District Court’s calculation was
erroneous because the government “failed to establish that
Sterlingov and/or Bitcoin Fog knowingly received or
transacted with any criminal proceeds or funds,” Appellant Br.
at 93–94, and that to the extent that they did, the government
only attributed approximately $78 million to known darknet
markets, id. at 95. The government responds that Sterlingov
has failed to meet his burden of providing “sufficient
information to determine the amount of criminally derived
funds” when “he presented no information about the other
funds that Bitcoin Fog mixed.” Gov’t Br. at 95; see also S.A.
336. In other words, under the Guidelines, the burden was on
Sterlingov to show that of the approximately $400 million that
was pushed through Bitcoin Fog, only $78 million of it could
be attributed to criminal means, while the other $322 million
was completely legitimate.

     The government is correct that Sterlingov carries the
burden of detangling the funds, and it is also correct that
Sterlingov has failed to satisfy his burden here—Sterlingov
makes no argument regarding the allegedly legitimate funds,
and he further presented no constitutional or statutory objection
to that burden allegation. We therefore reach no holding on
those questions. 12

12
   Sterlingov has further cursorily asserted that the District Court
erred in admitting co-conspirator statements in violation of Federal
                                 38
                                III.

    For the reasons outlined above, the decisions of the
District Court are affirmed.




Rule of Evidence 801(d)(2)(E). But in making his arguments,
Sterlingov fails to identify the specific statements that should have
been excluded. Likewise, Sterlingov has alleged in a single
paragraph that the government’s evidence was insufficient. But
Sterlingov does not explain why the evidence is insufficient.
Because Sterlingov has alluded to these arguments only “in the most
skeletal way,” leaving the Court to “put flesh on its bones,” we hold
that he has forfeited these claims. Al-Tamimi,
916 F.3d at 6
(citation
modified).