When are police dog sniffs legal? We all know that man's (and woman's) best friend is not only good for company and fetching frisbees, but also for police investigations.
However, while police dogs are commonly used to detect things like bombs, drugs, and even blood, the results of a law-enforcement canine's sniff can't always be used in court.
So when are dog sniffs allowed? Like many legal questions, the answer depends on the specific circumstances surrounding the sniff. Consider the following scenarios:
At Your Home
In general, when a police dog is used to uncover illegal activity or substances at a person's home, it counts as a search under the Fourth Amendment. Unreasonable searches and seizures by the government are generally prohibited unless officers obtained a warrant or had probable cause first.
This applies even to dog sniffs performed outside a suspect's home, the U.S. Supreme Court recently held.
Therefore, police cannot use dog sniffs to "search" a person's home -- inside or outside -- without first obtaining a warrant.
Around Your Vehicle
However, a warrantless dog sniff is allowed if it's performed around a person's vehicle.
This came up in another U.S. Supreme Court case, in which justices upheld a warrantless dog sniff of a car that led to the discovery of contraband. The Court found that a warrant was not required because the dog sniff didn't appear to invade any of the citizen's other reasonable expectations of privacy.
Still, the Court did suggest that if police "had improperly extended the duration of the stop to enable the dog sniff to occur," then that likely would have made the officers' actions unlawful.
In a Public Place
What about situations where dog sniffs are used in public, like at a mall or at an airport?
The Supreme Court has, in fact, ruled that warrantless dog sniffs are OK at airports. That's because the "exposure of ... luggage, ... located in a public place, to a trained canine" is not considered a Fourth Amendment "search."
As a dog sniff doesn't require opening a bag or rummaging through its contents, it's "much less intrusive than a typical search," the Court explained. A similar argument can be made for dog sniffs in other public places as well.
Still, as dog sniffs continue to be challenged in court, you'll want to consult an experienced criminal defense attorney to see if it's a potential issue in your particular situation.