Sixth Circuit Clarifies GPS-Based Vehicle Seizure and Intrinsic Evidence in Drug Conspiracy Prosecutions

Introduction

In United States v. Christopher Simpson, Marquise Figures, & Antuan Wynn (6th Cir. May 21, 2025), the Sixth Circuit addressed a series of interlocking Fourth Amendment, evidentiary, and sentencing issues arising from a large-scale narcotics distribution conspiracy centered in Toledo, Ohio. Federal agents used a GPS tracker to locate and seize a Dodge Charger traded for fentanyl, and later discovered powder cocaine, crack, and fentanyl moving through a chain of suppliers, middlemen, and street-level distributors. Defendants Simpson, Figures, and Wynn were convicted of drug conspiracy under 21 U.S.C. § 846 and related charges. On appeal, they challenged:

Whether officers lawfully seized and searched the Tracker-equipped vehicle without a new warrant;
Admissibility of pre-conspiracy drug evidence under Rule 404(b);
The scope of permissible jury instructions and the buyer-seller “narrow exception” to conspiracy liability;
Sentencing determinations under the U.S. Sentencing Guidelines, including drug-quantity calculations, obstruction enhancements, firearm and premises enhancements, and minor-participant reductions;
Alleged variance between the single‐conspiracy indictment and proof of separate cocaine and fentanyl conspiracies.

Summary of the Judgment

The Sixth Circuit unanimously affirmed all convictions and sentences. Key holdings include:

Fourth Amendment: Officers had probable cause to seize a vehicle that was itself forfeitable contraband under 21 U.S.C. § 853(a) and Ohio law. A GPS tracker lawfully placed under warrant remained valid after a change in registered ownership, and an inventory search after impoundment complied with established precedents (Carroll, Opperman, White, Jones).
Evidence and Jury Instructions: Drug evidence from a January 2021 traffic stop was intrinsic to the charged conspiracy and not subject to Rule 404(b). The buyer-seller narrow exception did not shield Figures or Wynn, as both had ongoing, interdependent dealings that implied an agreement to resell.
Variance: No prejudicial variance arose from proof of both cocaine and fentanyl trafficking. The evidence of a single, chain-style conspiracy was coherent, and the jury was properly instructed to consider each defendant separately.
Sentencing Guidelines:
- Drug-quantity findings (fentanyl for Simpson; cocaine for Figures and Wynn) rested on reliable co-conspirator testimony, wire intercepts, and other corroboration, satisfying the “plausible on the record as a whole” standard.
- Obstruction enhancement (§ 3C1.1) for Simpson upheld based on threats to a codefendant.
- Firearm (§ 2D1.1(b)(1)) and drug-premises (§ 2D1.1(b)(12)) enhancements for Wynn affirmed on clear-error review.
- Minor-participant reduction (§ 3B1.2) denial for Figures was not clearly erroneous.

Analysis

Precedents Cited

The court relied on a well-developed body of Fourth Amendment and sentencing precedents:

Carroll v. United States (267 U.S. 132 (1925)): Automobile exception for warrantless searches when probable cause exists that the vehicle itself is contraband.
South Dakota v. Opperman (428 U.S. 364 (1976)): Inventory searches of impounded vehicles are reasonable.
Florida v. White (526 U.S. 559 (1999)), United States v. Jones (565 U.S. 400 (2012)), United States v. Lumpkin (6th Cir. 1998): GPS tracking of vehicles under warrant does not become unlawful simply because ownership transfers.
United States v. Gardner (6th Cir. 2022), Histed (6th Cir. 2024), Tisdale (6th Cir. 2020): Guidelines drug-quantity rules permit inclusion of “reasonably foreseeable” quantities attributable to conspirators on a preponderance standard.
Whren v. United States (517 U.S. 806 (1996)): Officer motive is irrelevant to the objective Fourth Amendment analysis.
United States v. Mosley (6th Cir. 2022), Wheat (6th Cir. 2021), Parlier (6th Cir. 2014): The narrow buyer-seller exception to conspiracy liability, and the permissibility of chain conspiracies.
United States v. Watts (519 U.S. 148 (1997)): Acquitted conduct may be considered at sentencing under the Sentencing Guidelines (later action clarified that post-2024 § 1B1.3(c) was not retroactive).

Legal Reasoning

Vehicle Seizure & Search: The court began with the Fourth Amendment’s protection against unreasonable seizures and searches of “effects.” Recognizing that forfeiture statutes render an entire vehicle contraband if used in drug trafficking, officers had probable cause—based on intercepted calls and informant information—that the Charger was forfeitable. A warrant‐authorized GPS device remained valid after a change in registered ownership (Gibson, Sanchez-Jara). Once seized in a public place, the impoundment and inventory search complied with department policy, fully consistent with Opperman and Smith (6th Cir. 2007).

Intrinsic Evidence under Rule 404(b): Evidence of defendants’ drug-and-cash possession during an in-conspiracy traffic stop was intrinsic to the charged conspiracy, not “other‐act” evidence under Rule 404(b). Intrinsic evidence—any act that forms part of the same transaction or scheme—requires no separate 404(b) analysis (Barnes, 6th Cir. 1995).

Drug Conspiracy & Buyer-Seller Exception: To convict under § 846, the government must prove an agreement to commit drug offenses, knowledge of that agreement, and participation in it. A simple, isolated buyer-seller relationship is not enough, but repeated, standardized transactions over months—plus shared planning, pooling of funds, warnings of police, and mutual reliance—establish an implicit agreement to distribute (Mosley, Wheat). The defendants’ chain-style relationships (suppliers → middlemen → street distributors) formed a single conspiracy.

Variance Doctrine: Although trial evidence covered both cocaine and fentanyl, the proof pointed to one interlocking conspiracy with overlapping actors. No prejudice arose from multiple narcotics streams, and the jury was properly instructed to decide each defendant’s guilt separately (United States v. Carver, 6th Cir. 2006).

Sentencing Guidelines:

Drug-Quantity Findings: Co-conspirator testimony, wire calls, photographs, and admissions provided a “minimal indicium of reliability” for estimating total weights of fentanyl or cocaine base. Clear-error review upheld base offense levels under §§ 2D1.1(c)(4) & (c)(8).
Obstruction Enhancement (§ 3C1.1): Threatening a codefendant to suppress testimony justified a two-level increase.
Firearm Enhancement (§ 2D1.1(b)(1)): Possession of a revolver in a home used for drug trafficking fell squarely within the enhancement’s “presence” and “connection” standard.
Drug-Premises Enhancement (§ 2D1.1(b)(12)): Repeated trafficking at a residence used for storage and distribution satisfied the “principal use” test.
Minor-Participant Reduction (§ 3B1.2): Denial of a four-level reduction for Marquise Figures was not clearly erroneous in light of his regular wholesale distribution role.

Impact

United States v. Simpson, Figures & Wynn reinforces and refines critical doctrines in Fourth Amendment and federal drug-conspiracy law:

Warranted GPS tracking remains valid despite changes in ownership, and probable cause to forfeit a vehicle empowers its seizure and inventory search without additional warrants.
Evidence gathered mid-conspiracy is “intrinsic” and not subject to exclusion under Rule 404(b).
The narrow buyer-seller exception will not shield participants in recurring, interdependent drug networks.
Chain or “hub‐and‐spoke” conspiracies will be treated as single conspiracies where defendants know their role furthers a broader distribution network.
Conceded acquitted conduct rules (§ 1B1.3(c)) do not apply retroactively to pre-2024 sentences; sentencing courts may continue to consider acquitted conduct for Guideline calculations.

Practitioners should note the Sixth Circuit’s careful adherence to precedent while clarifying that facts establishing forfeiture-based probable cause and intrinsic evidence will routinely survive suppression and exclusion motions.

Complex Concepts Simplified

Probable Cause for Vehicle Seizure: Officers need only a fair probability that the car itself is forfeitable contraband, not that every item inside it is evidence of crime.

GPS Tracking Warrants: A valid warrant to place a tracker on a vehicle remains in effect even if the car is later sold, because probable cause was tied to the vehicle rather than a particular driver.

Intrinsic vs. 404(b) Evidence: Any act that “completes the story” of the crime charged is intrinsic and freely admissible; only truly separate bad acts require a 404(b) balancing test.

Buyer-Seller Exception: A one-off purchase does not create conspiracy liability, but repeated, planned transactions where the buyer resells to others do.

Chain Conspiracy: When suppliers, middlemen, and street dealers all share the same distribution goal, they form one conspiracy even if they never meet each other directly.

Acquitted Conduct in Sentencing: Pre-2024 sentences are not governed by the new § 1B1.3(c) exclusion of acquitted conduct; sentencing courts may consider conduct underlying dismissed or acquitted charges.

Conclusion

United States v. Simpson, Figures & Wynn delivers a thorough reaffirmation of core Fourth Amendment protections and federal drug-conspiracy doctrine, while bringing needed clarity to the use of GPS warrants, the scope of intrinsic evidence, and the application of sentencing enhancements. By tying vehicle forfeiture seizures to the forfeitable status of the car itself and preserving co-conspirator evidence for jury consideration, the Sixth Circuit equips law enforcement and courts with a robust framework for investigating and prosecuting large-scale narcotics networks without eroding constitutional safeguards.