## Facts

- Bradley Tobey was convicted by a jury of two counts of illegal sale of heroin based on two undercover purchases in February 1972.
- Between the two sales, an undercover agent made three recorded telephone calls to a person the agent believed was Tobey.
- In December 1972, the court ordered Tobey to provide recorded voice exemplars by repeating words used in the earlier calls.
- Police submitted the recorded calls and exemplars for spectrographic “voiceprint” comparison using a sound spectrograph to create and compare spectrograms.
- At trial, three prosecution experts described spectrographic voice identification; two opined Tobey’s exemplar matched the voice on the recorded calls.
- Cross-examination revealed methodological problems, including failure to account for differences between telephone-recorded speech and direct microphone recordings, lack of routine calibration/maintenance of the spectrograph, and limited validation for comparisons where samples were recorded months apart.
- Tobey objected to admission of the voiceprint evidence and appealed after conviction.

## Issues

1. Whether the trial court erred by admitting spectrographic “voiceprint” identification testimony without an adequate foundation establishing the technique’s reliability, general scientific acceptance, and reliable application in this case.

## Decision

- The Michigan Court of Appeals reversed Tobey’s convictions and remanded for a new trial.
- The court held the prosecution failed to lay an adequate foundation for admission of spectrographic voice identification evidence.
- The court treated the voiceprint testimony as improperly admitted corroboration of a key identification issue and not harmless error.

## Legal Principles

- Novel scientific identification evidence is admissible only if the proponent establishes, through an adequate foundation, that the technique has gained general acceptance in the relevant scientific community.
- Foundational proof must address not only claimed theory but also reliability of the specific procedures used, including controls for material recording differences, appropriate equipment maintenance/calibration, and empirical support for the comparison conditions presented.
- Scientific evidence offered to corroborate critical identification testimony carries substantial risk of undue weight; absent a proper foundation, its admission warrants reversal when it may have influenced the verdict.

## Conclusion

The court ordered a new trial because the prosecution did not demonstrate that spectrographic “voiceprint” identification was sufficiently accepted and reliably applied to justify its admission as expert identification evidence.


People v. Tobey, 231 N.W.2d 403 (Mich. Ct. App. 1975)