In many cases, the police threaten to call for a police canine to sniff around a stopped automobile. Sometimes, the threat is simply a ruse to get the suspect to consent to a search. In other circumstances, postal inspectors or the police will call for the dog to sniff a package. Other times it can be at the airport, train, or bus station sniffing for gun powder or explosives.

A criminal defense attorney must be vigilant in these circumstances to discover the training of the dog, the dog handler and the track record of the dog. A challenge can be mounted to a search based upon the use of canines, but unless it is accompanied by a searching inquiry led by defense counsel, the police have wide latitude in the use of evidence sniffing dogs.