Kyllo v. United States

Kyllo v. United States was a 2001 decision by the United States Supreme Court that 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 Danny Lee Kyllo's conviction for growing marijuana.