OCTOBER TERM, 2000
Syllabus
certiorari to the united states court of appeals for the ninth circuit
No. 99-8508. Argued February 20, 2001—Decided June 11, 2001
Suspicious that marijuana was being grown in petitioner Kyllo's home in a triplex, agents used a thermal-imaging device to scan the triplex to determine if the amount of heat emanating from it was consistent with the high-intensity lamps typically used for indoor marijuana growth. The scan showed that Kyllo's garage roof and a side wall were relatively hot compared to the rest of his home and substantially warmer than the neighboring units. Based in part on the thermal imaging, a Federal Magistrate Judge issued a warrant to search Kyllo's home, where the agents found marijuana growing. After Kyllo was indicted on a federal drug charge, he unsuccessfully moved to suppress the evidence seized from his home and then entered a conditional guilty plea. The Ninth Circuit ultimately affirmed, upholding the thermal imaging on the ground that Kyllo had shown no subjective expectation of privacy because he had made no attempt to conceal the heat escaping from his home. Even if he had, ruled the court, there was no objectively reasonable expectation of privacy because the thermal imager did not expose any intimate details of Kyllo's life, only amorphous hot spots on his home's exterior.
Held: Where, as here, the Government uses a device that is not in general public use, to explore details of a private home that would previously have been unknowable without physical intrusion, the surveillance is a Fourth Amendment "search," and is presumptively unreasonable without a warrant. Pp. 31-41.
(a) The question whether a warrantless search of a home is reasonable and hence constitutional must be answered no in most instances, but the antecedent question whether a Fourth Amendment "search" has occurred is not so simple. This Court has approved warrantless visual surveillance of a home, see California v. Ciraolo, 476 U. S. 207, 213, ruling that visual observation is no "search" at all, see Dow Chemical Co. v. United States, 476 U. S. 227, 234-235, 239. In assessing when a search is not a search, the Court has adapted a principle first enunciated in Katz v. United States, 389 U. S. 347, 361: A "search" does not occur—even when its object is a house explicitly protected by the Fourth Amendment—unless the individual manifested a subjective
27
Page: Index 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 NextLast modified: October 4, 2007