In People v. Jones, decided by the US Supreme Court in January 2012, the Court unanimously declares that placing a GPS device on a car without a warrant is a violation of the 4th Amendment. In this particular case, the FBI placed the GPS tracking device on the defendant’s car while the car was on public property. The police followed the defendant using the GPS device for a month and based on the data from the GPS device, they obtained a warrant, which then led to the seizure of cocaine.
However, it is the initial placement of the GPS device that was illegal and therefore everything that followed from that was “fruit of the poisonous tree”. The Supreme Court held that the placement of the device and the use of the device constitute a search under the Fourth Amendment.