Tacit Conspiracy with Dark Web Marketplace Operators: Fifth Circuit Affirms That Platform Facilitation Can Satisfy the Agreement Element in Narcotics Conspiracies

Introduction

In United States v. Shaughnessy, No. 24-10126 (5th Cir. Oct. 2, 2025), the Fifth Circuit affirmed a jury verdict and sentence arising from a multi-year narcotics trafficking enterprise conducted on dark web marketplaces (DWMs). The case breaks important ground within the Fifth Circuit by recognizing that a drug vendor’s sustained, mutually reinforcing relationship with DWM administrators and moderators—who knowingly design and maintain infrastructure to facilitate anonymous contraband sales—can support the “agreement” element of a drug-trafficking conspiracy, even where those administrators remain unidentified.

The defendant, Sean Shaughnessy, operated as a pseudonymous vendor on multiple DWMs, selling controlled substances and controlled substance analogues and converting proceeds into cash through a cooperating dark web currency exchanger. Investigations uncovered narcotics, ledgers linking him to platform accounts, intercepted international shipments, and a laptop repository containing both detailed transaction records and child pornography. A federal jury convicted him of two conspiracies (post-scheduling controlled substances and pre-scheduling analogues), one distribution count (methoxyacetyl fentanyl), and possession of child pornography. The district court imposed a 293-month aggregate sentence at the top of the advisory Guidelines range.

On appeal, Shaughnessy raised four principal claims:

Insufficiency of the evidence on the “agreement” element of the drug conspiracies;
Erroneous admission of testimony about his Bitcoin-to-cash dealings with a dark web exchanger (“Gold”), which he framed as impermissible character evidence of uncharged money laundering;
Abuse of discretion in admitting two uncharged videos of child pornography under Rule 404(b); and
Improper application of the five-level U.S.S.G. § 2G2.2(b)(7)(D) enhancement (600+ images) based on still images and videos found on his laptop.

The Fifth Circuit rejected each challenge and affirmed across the board.

Summary of the Opinion

The Court held that:

Conspiracy Sufficiency: A reasonable jury could find an “agreement” based on (i) a tacit, reciprocal arrangement between Shaughnessy and DWM administrators/moderators who knowingly provided the tools and protections essential to his narcotics business, and (ii) repeated bulk procurement from upstream foreign suppliers evidenced by intercepted parcels and ledgers. Identification of specific coconspirators by name was not required.
Bitcoin-to-Cash Testimony: Testimony about Shaughnessy’s use of “Gold” to convert Bitcoin to currency was intrinsic to the drug conspiracies because it explained how he monetized his illegal sales and completed the story of the offense. Given its intrinsic character, Rule 404(b) did not apply, and no plain error occurred.
Rule 404(b) Videos: Two uncharged child-pornography videos, each under ten seconds and discovered in the same archive as charged images, were admissible to show knowledge, intent, motive, plan, or opportunity regarding the possession count. The district court reasonably found their probative value was not substantially outweighed by unfair prejudice, especially with tailored limiting instructions.
Sentencing Enhancement: The district court did not clearly err in applying § 2G2.2(b)(7)(D). Crediting a forensic analyst’s file-by-file assessment that the defendant possessed 14 still images and 8 videos (with each video counting as 75 images for guideline purposes) was plausible on the record. NCMEC correspondence identifying only a “known series” of five images did not undermine the broader evidentiary showing.

Analysis

A. Precedents Cited and Their Influence

1) Conspiracy and Tacit Agreement

United States v. Chapman, 851 F.3d 363 (5th Cir. 2017); United States v. Shoemaker, 746 F.3d 614 (5th Cir. 2014); United States v. White, 219 F.3d 442 (5th Cir. 2000); United States v. Farias, 469 F.3d 393 (5th Cir. 2006): These decisions establish that conspiratorial agreement need not be express; it can be tacit and inferred from circumstantial evidence and concerted action.
United States v. Price, 869 F.2d 801 (5th Cir. 1989): Permits conspiracy convictions involving “unknown” coconspirators if evidence shows their existence and complicity.
United States v. Delgado, 672 F.3d 320 (5th Cir. 2012) (en banc): Articulates the “buyer–seller” limitation; a mere transactional relationship cannot alone sustain a conspiracy, but repeated collaboration advancing a distribution objective can.
United States v. Dukes, 139 F.3d 469 (5th Cir. 1998): Supports inferring a conspiracy from repeated bulk procurement coordinated with downstream redistribution.
United States v. Hinojosa, No. 22-10584, 2024 WL 841088 (5th Cir. Feb. 28, 2024): Analogous facilitation principle—club owners who actively enable drug sales can be conspirators with dealing patrons.
Persuasive out-of-circuit: United States v. Decker, 832 F. App’x 639 (11th Cir. 2020) (dark web vendor conspired with DWM admins who deliberately established platforms to assist illegal sales); United States v. Bondars, 801 F. App’x 872 (4th Cir. 2020) (administrator’s knowing creation and promotion of a platform for fraud supported conspiracy with users).

These authorities collectively enable the Fifth Circuit’s central move: recognizing that a DWM’s knowing design and maintenance of tools—escrow, encrypted messaging, dispute resolution, vendor ratings—used to conduct illegal sales, combined with a vendor’s sustained integration into and appeals to that infrastructure, can evidence a tacit, mutual plan to distribute narcotics. The opinion harmonizes the principle with Delgado by distinguishing mere transactional contacts from ongoing, mutually beneficial collaboration.

2) Intrinsic Evidence vs. Rule 404(b)

United States v. Yi, 460 F.3d 623 (5th Cir. 2006): Rule 404(b) addresses extrinsic acts; intrinsic evidence lies outside its ambit.
United States v. Coleman, 78 F.3d 154 (5th Cir. 1996); United States v. Williams, 900 F.2d 823 (5th Cir. 1990); United States v. Kloock, 652 F.2d 492 (5th Cir. 1981): Intrinsic evidence is admissible to “complete the story” of the crime, including acts inextricably intertwined or necessary preliminaries to the offense.
United States v. Valdez-Anguiano, 91 F.3d 139, 1996 WL 400195 (5th Cir. 1996) (unpublished); United States v. Mendez, 643 F. App’x 418 (5th Cir. 2016): Cash and proceeds can be intrinsic to a drug conspiracy.

Drawing on these cases, the Court deems the Bitcoin-to-cash evidence intrinsic because it explained how Shaughnessy monetized DWM sales and why he resorted to an anonymous exchanger after regulated platforms required source-of-funds verification. This “completes the story” of the conspiracies by showing proceeds flow and operational mechanics.

3) Rule 404(b) and Rule 403 in Child Pornography Cases

United States v. Beechum, 582 F.2d 898 (5th Cir. 1978) (en banc): Two-step test—non-character relevance and Rule 403 balancing.
United States v. Layne, 43 F.3d 127 (5th Cir. 1995); United States v. Goff, 155 F. App’x 773 (5th Cir. 2005); United States v. Naidoo, 995 F.3d 367 (5th Cir. 2021): Uphold admission of uncharged pornography to prove knowledge of possession.
United States v. Grimes, 244 F.3d 375 (5th Cir. 2001); United States v. Caldwell, 586 F.3d 338 (5th Cir. 2009): Grimes is the exception where extrinsic evidence was far more inflammatory; Caldwell emphasizes Grimes’s narrowness.
United States v. Kinchen, 729 F.3d 466 (5th Cir. 2013); United States v. Jackson, 339 F.3d 349 (5th Cir. 2003): Heightened scrutiny applies to 404(b) evidence; rulings must reflect careful Rule 403 balancing.

The Court’s 404(b)/403 analysis aligns with these authorities: the videos bore directly on knowledge and were not materially more inflammatory than already-charged images, and a targeted limiting instruction further reduced prejudice risk.

4) Sentencing Enhancements and Deference

United States v. Landreneau, 967 F.3d 443 (5th Cir. 2020); United States v. Gomez-Valle, 828 F.3d 324 (5th Cir. 2016): Guideline application is reviewed de novo; factual findings are reviewed for clear error.
United States v. Rodriguez, 523 F.3d 519 (5th Cir. 2008): Government must prove enhancements by a preponderance of reliable evidence.
United States v. Perez, 217 F.3d 323 (5th Cir. 2000); United States v. Sotelo, 97 F.3d 782 (5th Cir. 1996): Credibility determinations at sentencing receive substantial deference.
United States v. Cordy, 560 F.3d 808 (8th Cir. 2009) (persuasive): Upholds reliance on experienced agents for age determinations in child-exploitation cases.
United States v. Juarez-Duarte, 513 F.3d 204 (5th Cir. 2008): Clear error requires findings to be implausible in light of the whole record.

These cases support the district court’s reliance on an analyst’s detailed, file-specific age assessments and the videos-as-75-images guideline rule. NCMEC’s limited “known series” notation did not negate the broader evidentiary showing.

B. The Court’s Legal Reasoning

1) Conspiracy: Platform Operators and Upstream Suppliers

The Fifth Circuit’s central holding is that a jury could infer a tacit conspiratorial agreement from Shaughnessy’s years-long, mutually beneficial relationship with DWM administrators and moderators. The Court emphasized:

DWMs are purpose-built for anonymity and illegal commerce, with 95–99% illicit listings;
Administrators and moderators set vendor policies, offer escrow, dispute resolution, ratings, and encrypted messaging;
Shaughnessy used at least sixteen DWMs, sought moderator assistance, publicly referenced account issues, escrow balances, and reactivations (e.g., “over 20k in escrow,” “back up and running,” “bags are heavy”); and
Ledgers and customer testimony corroborated actual narcotics distributions tied to these platforms.

By analogizing to Hinojosa (club owners as enablers of drug sales), and aligning with Decker and Bondars (dark web operators as partners-in-crime), the Court distinguished this case from a mere buyer–seller relationship. It found the platform’s designed facilitation and the vendor’s sustained use and dependence adequate to show a shared design—i.e., a “meeting of the minds”—even if administrators remain “unknown” in identity (per Price).

Separately, the Court held that repeated, bulk shipments from China to the defendant’s post office box—coupled with downstream sales and distribution paraphernalia—permitted an inference of a mutual plan with upstream suppliers to import and redistribute contraband (per Dukes).

2) Intrinsic Evidence: Bitcoin-to-Cash Through “Gold”

Although the Government mistakenly uttered “money laundering” at trial (after which the court immediately warned counsel), the panel concluded that the substance of the testimony was intrinsic to the drug conspiracies. It explained how Shaughnessy liquidated illegal proceeds after regulated exchanges demanded identity and source-of-funds checks he could not satisfy. Demonstrating the proceeds’ flow and the operation’s mechanics “completed the story” of the crime and therefore fell outside Rule 404(b).

3) Rule 404(b)/403: Two Uncharged Videos

The district court admitted two brief uncharged videos from the same archive as the charged images to prove knowledge of possession. Applying Beechum, the Fifth Circuit held the videos were relevant to non-character issues (knowledge/intent) and not unfairly prejudicial because:

They were not materially more inflammatory than the charged images (distinguishing Grimes); and
The district court issued a careful limiting instruction, permitting use of the videos only if the jury first found beyond a reasonable doubt from other evidence that the defendant committed the charged possession, and only for knowledge, intent, motive, plan, or opportunity.

That disciplined approach satisfied Fifth Circuit precedent requiring calibrated 403 balancing and limiting instructions in sensitive 404(b) contexts.

4) Sentencing: § 2G2.2(b)(7)(D) (600+ Images)

The enhancement turned on whether the defendant’s offense “involved 600 or more images,” with each video counting as 75 images. Crediting the forensic analyst’s testimony that Shaughnessy possessed 14 images and 8 videos (i.e., 14 + 8×75 = 614), the panel found no clear error. It emphasized:

The district court extensively vetted the analyst’s training and methodology (body size, absence of secondary sexual characteristics) and made on-the-record credibility findings; and
NCMEC’s “known series” reference does not purport to exhaustively classify all files; it therefore does not undermine the agent’s file-by-file assessment.

The determination was “plausible in light of the record as a whole,” warranting deference.

C. Impact and Future Implications

1) Conspiracy Liability in Platform-Mediated Drug Markets

This opinion is a significant Fifth Circuit marker for prosecuting online drug vendors. It confirms that:

The government need not identify platform operators by name to meet the conspiracy “agreement” element; it may rely on circumstantial proof of a tacit, mutually reinforcing relationship with DWM administrators/moderators who design and maintain tools for anonymous illegal commerce.
Years-long integration into such tailored platforms and demonstrated reliance on administrative support, escrow, and dispute resolution can defeat “buyer–seller” defenses.

Expect the government to cite Shaughnessy to argue that dark web platform operators—if shown to knowingly facilitate illegal transactions—qualify as coconspirators, allowing vendors’ conspiracy convictions even absent identification or direct communications. The logic may also apply to other illicit platform contexts (fraud, counterfeit goods) where administrators knowingly architect and maintain criminally purposed infrastructure.

Importantly, this principle targets platforms intentionally structured to facilitate illegal transactions. It does not implicate mainstream platforms that prohibit illicit activity and lack evidence of knowing facilitation.

2) Proceeds Evidence as Intrinsic

By endorsing proceeds conversion as intrinsic evidence, the Fifth Circuit reinforces prosecutors’ ability to explain how a digital trafficking enterprise operates end-to-end—including cash-outs through anonymizing services—without triggering Rule 404(b). Defense counsel should be prepared to address intrinsic-evidence arguments with specificity, especially where evidence connects the proceeds closely to the charged transactions (e.g., blockchain tracing “one or two steps away” from DWMs).

3) 404(b) Knowledge Evidence in Child Pornography Prosecutions

The decision reflects the Fifth Circuit’s steady approach to admitting uncharged pornography for knowledge/intent in possession cases, provided the court:

Vets content for proportionality relative to charged material;
Undertakes explicit Rule 403 balancing; and
Issues tailored limiting instructions.

Grimes remains a cautionary outlier where extrinsic evidence is categorically more inflammatory than the charged material.

4) Sentencing Under § 2G2.2

Shaughnessy underscores that:

Courts may rely on qualified forensic analysts (even if not medical experts) for age assessments based on observable characteristics;
NCMEC “known series” labels do not define the full scope of child pornography in a case; and
The videos-as-75-images rule remains operative unless and until amended by the Sentencing Commission.

Sentencing challenges will likely turn on credibility and the sufficiency of record-supported methodologies—areas where district courts receive substantial deference.

Complex Concepts Simplified

Dark Web: An overlay network accessible via special software (e.g., Tor) that masks user identities and locations. DWMs are marketplaces on the dark web, often used to trade contraband.
Controlled Substance Analogue: A substance with a chemical structure and effect similar to a scheduled controlled substance. Under federal law, analogues intended for human consumption are treated like the scheduled drug for prosecution.
Conspiracy “Agreement”: Prosecutors need not show an explicit pact. A tacit agreement can be inferred from concerted actions and mutual support toward a shared illegal goal, even with unidentified coconspirators.
Buyer–Seller Rule: A one-off purchase or sale is insufficient to prove conspiracy, but a recurring, cooperative relationship furthering distribution can establish the required agreement.
Intrinsic vs. Extrinsic Evidence: Intrinsic evidence directly explains or completes the story of the charged crime and is not subject to Rule 404(b). Extrinsic evidence involves “other acts” and must meet 404(b) relevance and Rule 403 balancing.
Rule 404(b): Bars character propensity evidence but permits other-acts evidence for non-character purposes (e.g., knowledge, intent, plan), subject to Rule 403 (unfair prejudice vs. probative value).
§ 2G2.2(b)(7)(D) Enhancement: A five-level increase applies if the offense involves 600+ images of child pornography. For Guidelines counting, each video equals 75 images.
NCMEC “Known Series”: A designation for images matched to known victims/series. It is not an exhaustive classification of all qualifying child pornography in a case.

Conclusion

United States v. Shaughnessy cements within the Fifth Circuit a consequential principle for digital-age drug prosecutions: when a vendor’s narcotics enterprise is enabled by platform operators who knowingly create and maintain infrastructure tailored to anonymous illegal sales—and the vendor repeatedly relies on that infrastructure and engages with moderators to keep the operation running—a jury may infer the conspiracy’s “agreement” element from that tacit, reciprocal relationship. The opinion also clarifies that proceeds-conversion evidence may be intrinsic to a drug conspiracy, endorses careful use of Rule 404(b) knowledge evidence in child pornography cases, and reaffirms deference to district courts’ credibility determinations underpinning § 2G2.2 enhancements.

Practically, Shaughnessy equips prosecutors with a roadmap to prove platform-mediated conspiracies without naming administrators, while reminding trial courts to scrutinize sensitive evidence with targeted instructions and balancing. For defense counsel, it signals the need to differentiate neutral or unintended platform support from knowing facilitation, and to rigorously contest the intrinsic characterization of proceeds evidence. As online criminal ecosystems evolve, Shaughnessy provides a durable analytical framework for aligning traditional conspiracy principles with modern, anonymized marketplaces.