Antoine Jones was a co-owner of Levels, a Washington nightclub. He was suspected of trafficking cocaine on the side, and a joint FBI-D.C. police team covertly attached a GPS device to his Jeep without first obtaining a warrant.
He was eventually tracked to suburban Maryland, where law enforcement officers discovered nearly 100 kilograms of the illegal narcotic, along with about $850,000 in cash. He was later sentenced to life in prison.
The court was being asked to decide whether such surveillance violated the Fourth Amendment and whether in this case it should be considered a "search," a "seizure," or both.
The Constitution says in "the right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated."
Government attorney Michael Dreeben met stiff resistance from the court when he suggested police have broad authority to conduct surveillance without first establishing "probable cause," a legal standard requiring a warrant.
More here: Justices to decide police use of GPS devices on suspects' cars - CNN.com