## Facts

- Federal prosecutors tried Luis Carbone in the District of Puerto Rico for cocaine offenses arising from an undercover operation involving a half‑kilogram transaction.
- An undercover agent used a body recorder to capture conversations during the deal; parts of the recordings were inaudible.
- The government created an “enhanced” version of at least one recording by reducing background noise to improve audibility.
- At trial, the government offered testimony describing the recording equipment, how the recordings were made and handled, the enhancement process, and identification of voices by participants or witnesses to the conversations.
- The court allowed jurors to use written transcripts while listening to the recordings, instructing that the recordings—not the transcripts—were the evidence and that transcripts were only a listening aid.
- The jury convicted Carbone of (1) conspiracy to distribute cocaine, and (2) aiding and abetting possession with intent to distribute, and (3) aiding and abetting distribution.
- On appeal, Carbone challenged the admission of the recordings (including the enhanced tape), the use of transcripts, the sufficiency of the conspiracy evidence, and the denial of a post‑trial in camera hearing regarding alleged perjury by a government witness.

## Issues

1. Whether the district court abused its discretion by admitting tape recordings where the defense challenged authentication, inaudibility, and the admissibility of an enhanced recording.
2. Whether the district court erred by permitting jurors to use transcripts while listening to the recordings.
3. Whether the evidence was sufficient to permit a rational jury to find beyond a reasonable doubt that Carbone knowingly joined a conspiracy to distribute cocaine.
4. Whether the district court abused its discretion by declining to hold a post‑trial in camera hearing to investigate alleged perjury by a government witness.

## Decision

- The First Circuit affirmed Carbone’s convictions on all counts.
- The court held the recordings were properly admitted: the government laid an adequate foundation, the inaudible portions were not so substantial as to render the remainder misleading, and enhancement to improve audibility was not inadmissible per se when properly authenticated.
- The court held it was not error to allow transcripts as listening aids where the jury was instructed that the recording controlled and the transcript was not independent evidence.
- The court held the conspiracy evidence was sufficient under the standard that views the evidence in the light most favorable to the verdict.
- The court held the district court did not abuse its discretion in refusing a post‑trial in camera hearing because the showing of perjury did not warrant such an inquiry.

## Legal Principles

- To admit audio recordings, the proponent must establish a foundation that the recordings accurately reproduce the conversations and are accurate, authentic, and trustworthy; once established, the opponent bears the burden to show inaccuracy.
- Recordings are not excluded merely because portions are inaudible; exclusion is warranted only if the inaudible parts are so substantial that the remainder is more misleading than helpful, and the determination is committed to the trial judge’s discretion.
- An enhanced recording designed to improve audibility (such as noise reduction) is not inadmissible per se; it may be admitted if properly authenticated and shown not to distort substantive content.
- A jury may use transcripts to assist in understanding recordings if the court gives clear limiting instructions that the recording is the evidence and controls over any discrepancy in the transcript.
- Appellate review of evidentiary admission decisions concerning recordings and transcript aids is for abuse of discretion.

## Conclusion

The First Circuit affirmed Carbone’s cocaine convictions, concluding that the district court acted within its discretion in admitting authenticated recordings despite partial inaudibility and enhancement, allowing transcripts only as aids with limiting instructions, finding sufficient evidence of conspiracy, and rejecting a post‑trial request for an in camera perjury hearing absent an adequate showing.


United States v. Carbone, 798 F.2d 21 (1st Cir. 1986)