## Facts

- A federal grand jury in the Northern District of Illinois investigated possible federal gambling offenses.
- The grand jury possessed voice recordings obtained under court orders and sought voice exemplars from about 20 subpoenaed individuals, including Antonio Dionisio, for comparison.
- Each subpoenaed witness was advised he was a potential defendant, shown a transcript of an intercepted conversation, and instructed to read it aloud into a recording device at a nearby U.S. Attorney’s office.
- Dionisio refused to provide a voice exemplar, asserting Fourth and Fifth Amendment objections.

## Issues

1. Whether compelling a grand jury witness to provide a voice exemplar violates the Fifth Amendment privilege against self-incrimination.
2. Whether a grand jury subpoena compelling appearance to provide a voice exemplar constitutes a Fourth Amendment “seizure” requiring a preliminary showing of reasonableness.
3. Whether compelling a voice exemplar unreasonably intrudes on a protected privacy interest under the Fourth Amendment, including when many witnesses are subpoenaed.

## Decision

- The Supreme Court reversed the court of appeals and remanded.
- Compelling a voice exemplar for identification purposes does not violate the Fifth Amendment because it is not testimonial or communicative.
- A subpoena to appear before a grand jury is not a Fourth Amendment “seizure” requiring a preliminary judicial showing of reasonableness.
- Requiring a voice exemplar did not infringe any valid Fourth Amendment interest because the voice is an identifying physical characteristic ordinarily exposed to the public.

## Legal Principles

- The Fifth Amendment protects against compelled testimonial or communicative evidence, not compelled displays of physical characteristics used for identification.
- Compulsion to provide identifying physical evidence (including speaking for identification) is generally outside the Fifth Amendment privilege when the content of the utterance is not used.
- Grand jury subpoenas compelling a witness’s appearance are not treated as Fourth Amendment seizures and are not conditioned on a preliminary reasonableness showing.
- There is no legitimate expectation of privacy in physical characteristics constantly exposed to the public, including the sound of a person’s voice; compelled voice exemplars, without bodily intrusion, ordinarily do not implicate Fourth Amendment privacy interests.

## Conclusion

The Court held that a grand jury may compel a witness to appear and provide a voice exemplar for identification without violating the Fourth or Fifth Amendments and without any required preliminary showing that the demand is reasonable.


United States v. Dionisio, 410 U.S. 1 (1973)