"A well-trained dog and a very good, well-trained handler can find explosives with little or no false alarms, " Beltz said.

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Justice Kagan and the two justices who joined her concurrence considered a trained drug-detection dog to be a device not in general public use, and on those grounds would have found its use unconstitutional in light of Kyllo.

FORBES: Supreme Court Finds The Use Of A Drug-Sniffing Dog To Investigate A Home Unconstitutional

To test their theory they monitored the daily outdoor routines of two people, one was alone and the other was accompanied by a dog trained to ignore passers-by so it would initiate social contact.

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The trained dog reportedly sensed something suspicious about -- or near -- a vehicle parked close to the West Wing, and sat down beside the four-door sedan.

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