One who knocks on a home's front door is an invitee or licensee, justifying ingress to the home by solicitors, hawkers and peddlers of all kinds. This implicit license typically permits the visitor to approach the home by the front path, knock promptly, wait briefly to be received, then leave. Thus, a police officer not armed with a warrant may approach a home and knock, precisely because that is no more than any private citizen might do.
Acting on an unverified tip that marijuana was being grown in defendant's home, the officers used a trained police dog to explore the area around the home in hopes of discovering incriminating evidence. They were gathering information in an area belonging to defendant and immediately surrounding his house — its curtilage, which enjoyed protection as part of the home itself. And they gathered that information by physically entering and occupying the area to engage in conduct not explicitly or implicitly permitted by the homeowner. The officers entered the boundaries of the curtilage, the front porch being a classic example of a constitutionally protected area. The Supreme Court of Florida approved a suppression of evidence, finding no probable cause for the Fourth Amendment search, rendering invalid the warrant based upon information gathered in that search. Certiorari was granted.
Was the government’s use of trained police dogs to investigate the home and its immediate surroundings a ‘search’ within the meaning of the Fourth Amendment?
On March 26, 2013, by a 5-4 margin, the Supreme Court held that the government's use of trained police dogs to investigate the home and its immediate surroundings is a "search" within the meaning of the Fourth Amendment, thus affirming the Florida Supreme Court. While an officer not armed with a warrant could approach a home and knock, because any private citizen might do so, introducing a trained police dog to explore the area around the home in hopes of discovering incriminating evidence was something else. There was no customary invitation to do that. That the officers learned what they learned only by physically intruding on defendant's property to gather evidence was enough to establish that a Fourth Amendment search occurred.