On January 23, 2012 the Supreme Court rule unanimously that police must get a search warrant before using a GPS device to track criminal suspects. Justice Scalia wrote the opinion for this case which involved Washington D.C. drug kingpin, Antoine Jones. Jones was partially convicted because the police installed a GPS device and tracked his movements on public roads for 28 days. Installing a GPS device on a suspect's vehicle to monitor movements now constitutes a "search" under 4th Amendment protection for unreasonable searches and seizures. The justices affirmed a panel from the US Court of Appeals for the D.C. Circuit. The panel held that evidence of Jones's frequent trips to a house that had nearly $1 million in cash and drugs had to be thrown out.
There was a split amongst the court with regards to how far this decision reaches. The majority (Scalia, Roberts, Kennedy, Thomas, and Sotomayor) said even if a device was installed without having to trespass on Jones's property, there still may have been "an unconstitutional invasion of privacy," but the present case did not require that they answer this question.