Federal Rules of Audio Evidence

Federal courts have several rules and standards regarding admission of audio evidence.microphone image by Alison Bowden from Fotolia.com

Audio evidence such as wiretaps, voice mails and other recorded media must meet certain legal standards before it may be admitted as evidence in a federal court. The process is based on legal precedents codified into federal statutes regarding evidence and civil procedure. Expert witnesses in forensic audio or other fields should familiarize themselves with the rules of audio evidence before testifying in federal court.

United States vs. McKeever

The case of United States vs. McKeever, 169 F. Supp. 426 (SDNY 1958), provided the foundations of the rules for admissibility of audio evidence in federal court. The case established seven tenets to prove the authenticity of a recording: (1) the recording device was capable; (2) the operator was competent to use the device; (3) the recording is authentic and correct; (4) the recording has not been edited; (5) the recording has been preserved in a manner shown to the court; (6) the identity of those speaking on the recording can be authenticated; and (7) the recorded conversation was made "in good faith without any kind of inducement."

A federal court usually determines the admissibility of audio evidence before the start of trial. During a pretrial hearing, opposing counsels may submit audio evidence along with reports from audio experts that vouch for its authenticity. In many cases, attorneys on both sides will question these experts in court to determine their competence to provide testimony. This process is known as Voir Dire. At its conclusion, the federal judge rules on whether she finds the expert competent to testify as well as whether the audio evidence is admissible.

Beyond the authenticity of the evidence, admissibility also depends on how it was obtained. For instance, if a law enforcement agent recorded audio evidence without an interception warrant, it would not be possible to show it to a jury no matter how incriminating the evidence.

In civil lawsuits, audio recordings are admissible if at least one party in the conversation consents to the recording. However, if a third party records incriminating evidence from two other people without their knowledge, not only is the evidence not admissible, but the person who makes the recording may be in violation of federal wiretap laws.

As the case proceeds, the court will evaluate audio evidence and its related testimony according to two standards.

The Frye standard is based on the 1923 case Frye vs. United States. In its ruling, the U.S. Circuit Court of Appeals for the District of Columbia ruled that expert testimony must rely on generally accepted scientific principles. Thus, interpretation of audio evidence using principles not accepted as legitimate science would not be admissible.

In 1993, the U.S. Supreme Court ruled in Daubert vs. Merrell Dow Pharmaceuticals that relevance, competence, and the materiality of the expert's testimony must also be taken into account. The Daubert standard requires not only that testimony be based on scientific principles, but that the expert be accepted as such among his peers.