The hand-held camera shows heat in degrees of white light. So if police suspect a person is dealing drugs in a darkened lot, they can see the deal. And, if someone is using hot lamps to grow marijuana in a house, the police can see the intense amount of heat leaving that house's roof. Since use of thermal cameras became more common over the last few years, the Statewide Narcotics Taskforce reports a drop in the number of persons found growing marijuana indoors. Five indoor locations were raided and 36 plants were destroyed in 1996, according to the taskforce.
Police have more success finding marijuana growing outside, where the hardy plant thrives.
Persons who have been arrested for growing marijuana have appealed to state and federal courts that police using thermal imaging violated their right to privacy. If they suspect drugs anywhere, they can do anything, it seems. The U.S. Supreme Court has what could be a precedent setting case under review, based on an arrest using thermal cameras. In 1996, two Seymour men were charged with cultivating marijuana after police used thermal imaging to detect the heat from their growing lamps. They appealed their conviction to the state Supreme Court and claimed their fourth amendment rights to privacy had been violated.