Sufficiency Without Perfect Procedure: Sixth Circuit Reaffirms Controlled-Buy Convictions on Circumstantial Evidence; Routine Drug-Testing Meets Daubert

Introduction

In United States v. Darryl Anthony McNeal, No. 24-5722 (6th Cir. Apr. 4, 2025) (not recommended for publication), a Sixth Circuit panel (Judges Thapar, Bush, and Larsen; opinion by Judge Thapar) affirmed a jury conviction for two counts of distribution and possession with intent to distribute methamphetamine under 21 U.S.C. § 841(a)(1). The case arose from two controlled buys orchestrated by Tennessee law enforcement on March 10 and March 13, 2020. A confidential source (CS) conducted both transactions, which were supported by officer testimony, video recordings, and lab analysis identifying the substances as methamphetamine.

McNeal challenged the sufficiency of the evidence and the admission of expert testimony from a government chemist (Agent Sharon Strickland) under Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993). He also attacked perceived imperfections in police procedures during the controlled buys, including pre-transaction searches, the handling and counting of buy funds, the limited line of sight to the hand-to-hand exchanges, and the probative value of videos that did not fully capture the transactions.

The Sixth Circuit affirmed, holding that:

Under Jackson v. Virginia, there was sufficient evidence for a rational jury to convict on both buys, even without indisputable video footage of the exchanges.
Discrepancies and procedural imperfections went to witness credibility and weight, not legal sufficiency.
Agent Strickland’s methodology and credentials satisfied Daubert for routine drug-identification testing, notwithstanding a prior exclusion in an unrelated case involving a different substance and novel testing.

Summary of the Opinion

Applying Jackson’s deferential sufficiency standard and emphasizing the appellate court’s limited role in reweighing evidence or assessing credibility, the panel concluded that the government’s evidence—comprising pre- and post-buy searches of the CS, contemporaneous phone calls with McNeal, law-enforcement surveillance, recovery of methamphetamine immediately after the buys, and corroborating video—was more than adequate for a rational juror to find that McNeal knowingly distributed a controlled substance on March 10 and March 13.

The court rejected McNeal’s contention that the videos were too limited to show a crime, noting that convictions can rest on circumstantial evidence and testimony alone. It further dismissed challenges to controlled-buy protocols—who searched the CS, whether funds were counted or videotaped, and whether officers directly observed drugs changing hands—as matters of credibility and weight. Finally, the court upheld the admission of the government chemist’s testimony, finding her training, experience, lab accreditation, and explanation of testing methods sufficient under Daubert.

Analysis

Precedents Cited and Their Influence

Jackson v. Virginia, 443 U.S. 307, 319 (1979) — Sets the sufficiency-of-the-evidence standard: viewing the evidence in the light most favorable to the prosecution, the question is whether any rational trier of fact could have found the essential elements of the crime beyond a reasonable doubt. The panel framed its review through Jackson and repeatedly emphasized that the bar for overturning a jury verdict on sufficiency grounds is high.
United States v. Crossley, 224 F.3d 847, 855–56 (6th Cir. 2000) — Reinforces that appellate courts do not reweigh evidence or make credibility determinations. The panel relied on Crossley to decline invitations to second-guess the jury’s credibility assessments, particularly regarding the confidential source and officer witnesses.
United States v. Forrest, 17 F.3d 916, 919 (6th Cir. 1994) — Identifies the elements under § 841(a)(1): the government must prove the defendant knowingly distributed a controlled substance. Forrest anchored the panel’s articulation of what the government had to prove for the March 10 and March 13 transactions.
United States v. Henley, 360 F.3d 509, 513 (6th Cir. 2004) — Confirms that circumstantial evidence alone can sustain a conviction. This authority undercut McNeal’s argument that limited or imperfect video footage was fatal to the government’s case.
United States v. Ledbetter, 929 F.3d 338, 352–53 (6th Cir. 2019) — Distinguishes sufficiency from weight of the evidence, locating attacks on discrepancies and credibility in the latter category for the jury to resolve. The panel cited Ledbetter to explain why inconsistencies about who searched the CS and the officers’ vantage point did not create a legal insufficiency.
Daubert v. Merrell Dow Pharm., Inc., 509 U.S. 579, 592–93 (1993) — Requires that expert testimony rest on scientifically valid reasoning or methodology. The panel held that Agent Strickland’s education, experience, accredited lab environment, and described testing procedures satisfied Daubert for routine drug identification.

Legal Reasoning

1) Sufficiency on March 10 and March 13

The panel recited a detailed sequence for both buys. For March 10, officers searched the CS and the vehicle beforehand, monitored the CS’s phone call to McNeal en route, watched the CS depart their vehicle, and subsequently retrieved the purchased substance from the CS, which lab tests identified as methamphetamine. The government corroborated these events with officer and CS testimony and video evidence.

Similarly for March 13, officers again searched the CS, the CS called McNeal, and McNeal drove his own vehicle to the meeting location. The CS went directly to McNeal’s car, purchased five ounces of methamphetamine, and promptly returned to law enforcement, who retrieved the substance and confirmed it was methamphetamine. This transaction was likewise supported by testimony and video.

Taking the record in the light most favorable to the government, the court held this evidence sufficed for a rational juror to find McNeal knowingly distributed a controlled substance on both dates, satisfying § 841(a)(1) as framed by Forrest.

2) Challenges to the Video Evidence

McNeal emphasized that the videos showed, at best, the CS’s lap, hand, or the car interior rather than the drugs changing hands. The panel responded that video is not necessary to prove distribution; circumstantial evidence and testimony can carry the day (Henley). Thus, even if the videos were unilluminating, the combination of searches, contemporaneous calls, surveillance, and immediate recovery of methamphetamine from the CS after each meet provided a firm basis for the jury’s verdict.

3) Alleged Deviations from Controlled-Buy Protocol

McNeal asserted three procedural flaws: inconsistent testimony about who searched the CS, a lack of videotaped (or even counted) buy funds, and an inability to visually confirm the exchanges because they occurred inside a vehicle or during times when officers lost direct view.

Search discrepancies: The panel acknowledged an inconsistency (one agent said he searched the CS and vehicle; the CS testified a female officer performed the searches both days). But such inconsistencies are classic credibility issues for the jury, affecting weight not sufficiency (Ledbetter). They do not negate the existence of evidence that, if believed, supports conviction.
Handling of buy funds: McNeal argued the absence of video showing the agent counting funds undermined reliability. The panel held there is no legal requirement that officers videotape—or even count—buy money. The question remains Jackson’s: whether any rational juror could find guilt beyond a reasonable doubt based on the totality of evidence. Here, testimony sufficed.
Line-of-sight limits: The fact that officers could not see the handoff (inside a car or while circling the block) again spoke to credibility and weight. The court’s role is not to second-guess the jury but to ensure that adequate evidence exists for a rational verdict—an inquiry satisfied by the testimony, corroborating circumstances, and post-buy recovery/testing of methamphetamine.

4) Admissibility of the Chemist’s Testimony under Daubert

Agent Sharon Strickland, a CBP chemist with a chemistry degree, eighteen years’ experience, prior testimony in multiple cases, and employment in an accredited lab, described how she identified and tested the substances purchased by the CS, concluding they were methamphetamine. The panel held this satisfied Daubert’s requirement that expert testimony be grounded in scientifically valid methodology.

The court rejected two specific defense attacks:

Lack of specificity: The panel found Strickland did, in fact, explain how she tested the evidence here.
Prior exclusion in another case: The earlier exclusion was in an unrelated matter involving a different substance and a novel testing method. By contrast, this case involved routine drug testing broadly accepted in courts and similar to testimony Strickland had provided previously. The prior exclusion had no bearing on the reliability of her methods here.

Impact

Although designated “not recommended for publication,” McNeal’s reasoning is likely to be cited persuasively in the Sixth Circuit and beyond for several practical propositions:

No perfection prerequisite for sufficiency in controlled buys: The ruling underscores that controlled buys need not be captured on clear video, and deviations or inconsistencies in field procedures (search personnel, money counting, line-of-sight) do not automatically defeat sufficiency. Prosecutors can rely on officer and CS testimony, pre- and post-transaction searches, surveillance, and lab results to meet Jackson.
Credibility attacks belong at trial: Defense challenges based on inconsistencies or the quality of surveillance are more potent before a jury than on appeal. McNeal reinforces that sufficiency review is not a vehicle for relitigating credibility.
Routine drug-identification testing satisfies Daubert: The opinion affirms a pragmatic approach to Daubert in narcotics cases: an experienced chemist working in an accredited lab and describing standard testing protocols will ordinarily clear the reliability threshold. Prior adverse Daubert rulings regarding the same expert carry little weight when the substance, method, and context differ.
Strategic implications:
- For prosecutors: Thoroughly document pre- and post-buy searches, contemporaneous communications, and secure prompt recovery and testing of substances. Even if video is imperfect, a layered evidentiary record is likely to survive sufficiency challenges.
- For defense counsel: Focus on pretrial Daubert litigation if there are genuine methodological flaws, and exploit credibility issues vigorously at trial. On appeal, frame arguments to target legal errors rather than factual disputes.

Complex Concepts Simplified

Controlled buy: A law-enforcement operation in which a confidential source, often searched and monitored beforehand, purchases contraband from a suspect, after which officers immediately recover the purchased substance for testing.
Confidential source (CS): A person working with law enforcement to obtain evidence, whose identity is typically protected. CS testimony and the procedures surrounding their interactions are common focal points in drug cases.
Direct vs. circumstantial evidence: Direct evidence proves a fact without inference (e.g., a clear video of a handoff). Circumstantial evidence requires inferences (e.g., pre- and post-buy searches plus immediate recovery of drugs). Both are valid; convictions can be based solely on circumstantial evidence.
Sufficiency vs. weight of the evidence: Sufficiency asks whether, viewing the evidence favorably to the prosecution, a rational juror could convict. Weight concerns how convincing the evidence is—a matter for the jury, not the appellate court, which does not reassess credibility.
Daubert standard: Governs admissibility of expert testimony. The expert’s methodology must be scientifically valid and reliably applied. Credentials, lab accreditation, and clear explanations of standard tests typically support admissibility in routine drug-identification contexts.
“Not recommended for publication”: Signals that the opinion is non-precedential within the circuit, though it can still be cited and may be persuasive to courts considering similar issues.

Conclusion

United States v. McNeal is a clear reaffirmation of two enduring principles in federal criminal practice. First, under Jackson, convictions stemming from controlled buys will withstand appellate scrutiny even when video evidence is limited and field procedures are less than pristine, so long as the testimonial and circumstantial record would allow a rational juror to find guilt beyond a reasonable doubt. Credibility disputes over who searched the CS, whether funds were counted on camera, or whether officers saw the hand-to-hand exchange are for the jury and do not convert into insufficiency on appeal.

Second, in routine drug cases, a qualified chemist employing standard, explained methods in an accredited laboratory satisfies Daubert. Prior exclusions of the same expert in different contexts do not undermine admissibility where the present methodology is conventional and adequately described.

Key takeaways:

Video is helpful but not required; circumstantial proof and credible testimony can sustain distribution convictions.
Procedural inconsistencies typically affect weight, not the legal sufficiency of the evidence.
Routine narcotics testing, competently described by a qualified chemist, will ordinarily be admitted under Daubert.

Though non-precedential, McNeal will likely be invoked in future Sixth Circuit cases to resist sufficiency challenges hinging on imperfect controlled-buy procedures and to support the admission of routine forensic drug-identification testimony.