Katz v. United States

Facts

FBI agents investigated Katz for transmitting wagering information by telephone. Agents visually observed Katz and predicted he would use a specific public telephone booth for several minutes at approximately the same time each morning. The telephone booth was constructed partly of glass, leaving Katz visible from the outside. To overhear his calls, agents attached an electronic listening and recording device to the outside of the booth. The device did not physically penetrate the wall of the booth. The agents acted without a warrant or prior approval from a judge or magistrate. They confined their surveillance to the brief periods when Katz used the booth, and they took care to record only his conversations. On one occasion when another person's statements were intercepted, the agents refrained from listening to them. The agents obtained six recordings, averaging some three minutes each. The recordings preserved Katz's end of conversations concerning the placing of bets and the receipt of wagering information. The Government introduced these sound recordings as evidence against Katz at his criminal trial over his objection.

Issues

1. Does the Government's electronic listening to and recording of a person's words in a public telephone booth constitute a search and seizure under the Fourth Amendment when the listening device does not physically penetrate the booth?
2. Does warrantless electronic surveillance violate the Fourth Amendment when agents act without prior approval by a judge or magistrate, even though investigation had established a strong probability of the crime and the agents confined the surveillance to the brief periods when the suspect used the booth?

Holding

The Government's electronic listening to and recording of Katz's words from outside the telephone booth violated the privacy on which he justifiably relied and so was a search and seizure, though nothing penetrated the booth. Because the agents never obtained a magistrate's prior approval, a constitutional precondition of this kind of electronic surveillance, and because the surveillance led to his conviction, the judgment was reversed.