“Co-Conspirator Liability and Cooperative-Witness Authentication”
Commentary on United States v. Reyes-Rosario, 79 F.4th ___ (1st Cir. 2025)

I. Introduction

United States v. Reyes-Rosario is a multi-faceted appellate opinion that solidifies two practical rules for federal criminal trials:

1. The First Circuit re-affirms Pinkerton co-conspirator liability, holding that a conviction on a substantive drug count can stand where the defendant’s guilt is predicated entirely on reasonably foreseeable acts of his confederates.
2. The court clarifies the low evidentiary threshold for authenticating physical evidence and video footage when a cooperating witness — rather than the recording officer — provides the foundation. The opinion expressly rejects the need for a “best evidence” approach or a rigorous chain-of-custody showing where distinctive identifying characteristics and first-hand knowledge are present.

Besides these two pillars, the judgment addresses Confrontation Clause limits, chain-of-custody challenges, and sentencing complaints, offering a comprehensive modern template for litigating complex drug conspiracies in the First Circuit.

II. Case Overview

Parties

• Appellant: Carlos J. Reyes-Rosario (“Reyes”), alleged leader of a public-housing drug point in Jardines de Cidra, Puerto Rico.
• Appellee: United States of America.

Procedural Background

• December 2017 — Grand jury indicts Reyes and 43 co-defendants on six counts. Count Six (firearms) is later acquitted.
• September 2022 — Jury finds Reyes guilty on five drug counts (Counts I-V).
• October 2022 — Defense files Rule 29 motion for acquittal; district court denies.
• March 2023 — Defendant receives concurrent sentences (168 months on Counts I-IV, 120 months on Count V).
• Appeal challenges: (1) sufficiency of evidence on Count II (heroin possession), (2) evidentiary rulings on video and seized contraband, (3) restrictions on cross-examination, (4) procedural and substantive reasonableness of sentence.

III. Summary of the Judgment

Chief Judge Barron (joined by Thompson & Gelpí, JJ.) affirms in all respects:

1. Count II Sufficiency — Adequate evidence of heroin distribution within 1,000 ft of a protected area under Pinkerton theory; conviction stands.
2. Evidentiary Rulings — Video footage and seized drugs properly authenticated by cooperating witness Claudio; no abuse of discretion.
3. Confrontation Clause — Limiting cross-examination on unrelated police corruption did not impede a “reasonably complete” attack on witness credibility.
4. Sentencing — No preserved procedural error; sentence substantively reasonable given breadth of conspiracy and U.S.S.G. §1B1.3 relevant-conduct doctrine.

IV. Analytical Commentary

A. Precedents Cited and Their Influence

• Pinkerton v. United States, 328 U.S. 640 (1946) — Core doctrine: a conspirator is liable for substantive crimes by co-conspirators if reasonably foreseeable and in furtherance of the conspiracy. The district court expressly instructed the jury on Pinkerton; the First Circuit blessed that reliance, underscoring the vitality of the doctrine nearly eight decades later.
• United States v. Salvador-Gutierrez, 128 F.4th 299 (1st Cir. 2025) (en banc) — Recent First Circuit articulation of Pinkerton. Cited to reinforce foreseeability as the key factual hinge.
• Fed. R. Evid. 901; United States v. Luna, 649 F.3d 91 (1st Cir. 2011); United States v. Blanchard, 867 F.3d 1 (1st Cir. 2017) — Collectively frame the “reasonable probability” test for authentication. Reyes-Rosario extends these precedents by accepting insider testimony over law-enforcement testimony even where officers are suspected of corruption.
• United States v. Anderson, 452 F.3d 66 (1st Cir. 2006) — Chain-of-custody case requiring heightened proof where drugs are not uniquely identifiable. Distinguished here: cooperative witness supplied distinctive identifiers, so rigorous chain not required.
• United States v. Gonzalez-Vazquez, 219 F.3d 37 (1st Cir. 2000) — Limits Confrontation Clause to witnesses’ own credibility; cross-examining about unrelated officers’ misconduct may be restricted.
• Samia v. United States, 599 U.S. 635 (2023) — Reaffirms that Confrontation Clause applies only to “witnesses against the accused.” Used to dismiss claim that non-testifying officers had to be produced for cross-examination.

B. Legal Reasoning of the Court

1. Count II Sufficiency via Pinkerton
   • The jury convicted Reyes on the conspiracy count (Count I).
   • Evidence showed he led the Cidra drug point, directly observed heroin sales, and communicated with street sellers.
   • These findings satisfied the five-part Pinkerton test (membership, in-furtherance, temporal overlap, foreseeability).
   • Because Reyes ignored this alternative theory on appeal, the conviction stands regardless of any aiding-and-abetting deficiencies.
2. Authentication & Chain of Custody
   • Rule 901 requires only a “reasonable probability” of genuineness.
   • Cooperative witness Claudio worked daily in the target house, was present during the warranted search, appears in the video, and identified unique packaging marks, drug colors, and firearm modifications.
   • Time-lapse “jumps” and absence of recording officers go to weight, not admissibility.
   • For drugs, distinctive packaging satisfied the “readily identifiable” exception; Anderson distinguished.
   • For other items, specific brand/modification details provided sufficient uniqueness.
3. Confrontation Clause
   • Defendant was permitted extensive cross-examination of Claudio about bias and plea benefits.
   • Inquiry into third-party police misconduct was collateral; its exclusion did not render cross-examination constitutionally deficient.
   • Officers who did not testify are not “witnesses against” the accused; their suppression raises no Sixth Amendment issue.
4. Sentencing
   • Procedural challenge unpreserved; plain-error standard unmet.
   • Substantive challenge failed; sentence within guideline range, supported by expansive scheme and leadership role.
   • Court’s reference to co-conspirator conduct mirrors U.S.S.G. §1B1.3(a)(1)(B) (jointly undertaken criminal activity).

C. Potential Impact of the Decision

1. Easier Government Path for Digital Evidence — Prosecutors may now rely on cooperating witnesses to authenticate body-cam or search-video footage even where law-enforcement participants are unavailable or tainted.
2. Defense Strategy Reassessment — Defense teams must directly rebut Pinkerton foreseeability on appeal; silence concedes the point.
3. Confrontation Clause Boundaries Reset — Attempting to impeach via non-testifying officers’ misconduct is likely futile unless it directly affects the testifying witness’s credibility.
4. Chain-of-Custody Doctrine — Distinctive characteristics may substitute for full chain-of-custody proof if a knowledgeable insider can link the item to the crime scene.

V. Complex Concepts Simplified

• Pinkerton Liability: Once you join a conspiracy, you are automatically responsible for crimes your partners commit to advance the plan, so long as those crimes were reasonably foreseeable. Think of a getaway driver being liable for the bank teller’s assault inside the bank.
• Authentication (Rule 901): Before evidence is shown to a jury, someone must say, “Yes, this is what it purports to be.” The bar is low — only a reasonable likelihood, not absolute certainty.
• Chain of Custody: A documented trail showing each person who handled the evidence. Required mainly when the object is not unique (e.g., white powder). Unnecessary when unique identifiers or witness familiarity provide assurance.
• Confrontation Clause: The Sixth Amendment right to face and question witnesses who testify against you. It doesn’t apply to people who never take the stand or whose out-of-court statements are not introduced.
• Procedural vs. Substantive Reasonableness (Sentencing): Procedural asks “Did the judge follow the right steps?” Substantive asks “Is the number of months fair and defensible?”

VI. Conclusion

United States v. Reyes-Rosario is less about novel doctrine and more about doctrinal consolidation. It fortifies prosecutorial tools in complex narcotics cases by:

• Re-endorsing Pinkerton as a potent vehicle for attributing substantive liability.
• Lowering practical hurdles for authenticating surveillance and physical evidence through insider testimony.
• Clarifying that Confrontation Clause objections must target the witness on the stand, not collateral actors.

Defense counsel confronting similar fact patterns must now directly counter foreseeability under Pinkerton and develop robust challenges to the “distinctive characteristics” rationale for authentication, lest those issues be deemed waived. On the judicial side, Reyes-Rosario supplies a meticulous, citation-rich roadmap for trial judges when ruling on authenticity, cross-examination scope, and sentencing explanations — a roadmap likely to influence First Circuit district courts for years to come.