## Facts

- Terry Waskin received a series of anonymous, threatening telephone calls forming the basis for an extortion prosecution.
- With Waskin’s consent, police recorded two threatening calls (the “extortion tapes”).
- An informant familiar with Robert Emmett Kelly’s voice listened to the extortion tapes and tentatively identified Kelly as the caller.
- Police obtained a recording of Kelly’s voice from a separate telephone call (the “control tape”).
- The extortion tapes and control tape were submitted for spectrographic “voiceprint” comparison.
- Lieutenant Ernest Nash, a voiceprint examiner, opined that the voices on the extortion tapes and the control tape were the same.

## Issues

1. Whether spectrographic voice identification (“voiceprint”) had achieved general acceptance in the relevant scientific community so that expert testimony and results derived from it were admissible as evidence.
2. Whether the prosecution’s foundational showing in this case was sufficient to establish the technique’s reliability and general scientific acceptance.

## Decision

- The California Supreme Court reversed the extortion conviction.
- The court held the prosecution’s evidentiary showing was insufficient to establish that voiceprint analysis was generally accepted as reliable in the relevant scientific community.
- The trial court erred by admitting Nash’s expert voiceprint testimony based on an inadequate foundation and reliance on prior authority rather than a developed record.
- Because the voiceprint evidence was the primary evidence of guilt, the error required reversal.

## Legal Principles

- Evidence derived from a new scientific technique is admissible only if the proponent establishes that the technique is generally accepted as reliable in the relevant scientific community.
- General acceptance is a foundational question that must be demonstrated through an adequate evidentiary record reflecting scientific opinion; it cannot rest on assumption or conclusory reliance on earlier cases.
- Testimony from a single advocate or proponent of the technique, without broader support showing acceptance (or addressing controversy), may be insufficient to satisfy the general-acceptance requirement.
- A court may leave open the possibility that the technique could be admitted in a future case if supported by a stronger, more balanced foundation establishing general acceptance.

## Conclusion

The court required a substantial, case-specific showing of general scientific acceptance before admitting results from a novel scientific identification method and reversed the conviction where voiceprint evidence was admitted without an adequate foundation and supplied the main proof of guilt.


People v. Kelly, 549 P.2d 1240 (Cal. 1976)