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Criminal ProcedureSearch and seizure

Kyllo v. United States

Supreme Court of the United States · Decided June 11, 2001 · Core case

Full citation

Kyllo v. United States, 533 U.S. 27 (2001).

VerifiedQuotes, pinpoints and citation checked word for word against the opinion; facts checked against the opinion before publication. October 20, 2026.

Danny Kyllo

homeownerpetitioner

United States

prosecution

The parties: Danny Kyllo v. United States.

Brief

Facts

In 1991, Agent William Elliott of the United States Department of the Interior suspected that marijuana was being grown in Danny Kyllo's home, part of a triplex in Florence, Oregon. Indoor marijuana growth typically requires high-intensity lamps. At 3:20 a.m. on January 16, 1992, Agent Elliott and Dan Haas used an Agema Thermovision 210 thermal imager to scan the triplex from a vehicle on the public street. Thermal imagers detect infrared radiation, invisible to the naked eye, and convert it into images based on relative warmth. The scan showed that the roof over the garage and a side wall were relatively hot compared to the rest of the home and substantially warmer than neighboring units. Elliott concluded that Kyllo was using halide lights to grow marijuana. Based on informant tips, utility bills, and the thermal imaging, a Federal Magistrate Judge issued a warrant authorizing a search of Kyllo's home. Federal agents searched the home and found an indoor growing operation with more than 100 plants. Indicted for manufacturing marijuana, Kyllo moved to suppress the seized evidence, and after the District Court denied the motion, he entered a conditional guilty plea.

Issue

Does the government's use of a thermal-imaging device aimed at a private home from a public street to detect relative amounts of heat within the home constitute a search under the Fourth Amendment?

Holding

Using a thermal-imaging device not in general public use to detect relative heat emanating from the exterior of Kyllo's home, in order to learn details about the interior of the home that could not otherwise have been obtained without physical intrusion, constituted a search under the Fourth Amendment. Because federal agents conducted this thermal scan without a warrant, the surveillance was presumptively unreasonable and unlawful.

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The Citation Code · citationcode.com/cases/kyllo-v-united-states