Kyllo v. United States

Case Date: 07/09/2025

Kyllo v. United States, 533 U.S. 27 (2001), held that the use of a thermal imaging device from a public vantage point to monitor the radiation of heat from a person's home was a "search" within the meaning of the Fourth Amendment, and thus required a warrant. Because the police in this case did not have a warrant, the Court reversed Kyllo's conviction for growing marijuana.