Many courts, including the U.S. Supreme Court, have held that the sniff of a trained police dog does not constitute a search under the fourth amendment. If the reaction of a police dog is used to establish probable cause for a search warrant, it is likely that the training received by both the dog and its handler will become an issue. Thus, documentation of training is a must for police canine units or officers. Any time an article is being detained under reasonable suspicion absent a police dog sniff, it should not be moved from one location to another. The dog should be brought to the article's location. This eliminates lengthy detention of suspects or suspects' luggage under uncertain conditions. A canine reaction not only constitutes probable cause for a subsequent search but also for an on-the-spot arrest or the issuance of an arrest warrant.