Also known as: dog sniffs · dog sniffing · canine sniff · drug dog search
Written by attorneys · grounded in primary & secondary sources — see below
An investigative technique employing a trained narcotics-detection dog to examine the exterior of luggage or a vehicle. The technique reveals only the presence or absence of contraband and therefore does not constitute a search under the Fourth Amendment.
Daniel Diaz was pulled over for a broken taillight. While the officer verified the registration, a drug dog arrived and circled the car. The dog alerted at the trunk within the time required to complete the paperwork, leading to a search that uncovered marijuana. The sniff supplied no independent Fourth Amendment violation because it occurred without extending the stop.
Demetrius Douglas approached a checkpoint where officers directed every car to stop briefly. A narcotics dog walked around the exterior of his vehicle and alerted. Officers then searched the car and found cocaine. The sniff itself added no separate constitutional defect because it disclosed only contraband.
Select any source to read its text and confirm it supports the definition.
Daphne Doyle surrendered her suitcase at an airport counter. Officers with reasonable suspicion removed the bag and held it for ninety minutes before a dog arrived and alerted. The prolonged seizure of the luggage violated the Fourth Amendment even though the subsequent sniff revealed only contraband.
No. A trained narcotics dog reveals only the presence or absence of contraband, so the sniff itself does not invade any legitimate privacy interest protected by the Fourth Amendment.
The sniff becomes unconstitutional when officers prolong the stop beyond the time needed to complete the original traffic mission without independent reasonable suspicion. Any added time converts the encounter into an unreasonable seizure.
Only briefly. A detention approaching ninety minutes exceeds the limited scope permitted by reasonable suspicion and becomes an unreasonable seizure even when the eventual sniff is not itself a search.
The alert can supply probable cause, but officers still must obtain a warrant or satisfy a recognized exception before opening the container. The sniff itself supplies no automatic right to search inside.
…possesses a privacy interest in the contents of personal luggage that is protected by the Fourth Amendment. Id. , at 13. A "canine sniff" by a well-trained narcotics detection dog, however, does not require opening the luggage. It does not expose noncontraband items that otherwise would remain hidden from public view, as…