Nationwide, courts can't agree whether the use of a "thermal imager" is actually a "search" for which a warrant is constitutionally required. Thermal imagers are used by police to confirm suspicions that residents are using great amounts of artificial light to grow marijuana. Some courts have said people don't have any expectation of privacy in the amount of heat emitted from their homes. But Commentator Lis Wiehl believes police should get a search before using these devices.
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