[JURIST] The US Court of Appeals for the Eleventh Circuit [official website] ruled [opinion, PDF] Wednesday that police must obtain a warrant to get a person’s cell phone location history from the cell phone provider. Police conducting a robbery investigation had obtained four people’s cell phone location histories after getting a “D-order” from a federal magistrate judge. The standard for getting a D-order, that it be “relevant and material” to an investigation, is lower than the probable cause standard required by the Fourth Amendment [text]. The appeals court found that such a warrantless search violated defendant’s Fourth Amendment rights: “In short, we hold that cell site location information is within the subscriber’s reasonable expectation of privacy. The obtaining of that data without a warrant is a Fourth Amendment violation.” An attorney for the American Civil Liberties Union (ACLU) [advocacy website] who argued the case as a friend of the court welcomed the ruling as “a resounding defense of the Fourth Amendment’s continuing vitality in the digital age.”

In April the US Supreme Court heard oral arguments [JURIST report] in a pair of cases dealing with warrantless searches of suspects’ cell phones. In February the Supreme Judicial Court of Massachusetts held that law enforcement must typically obtain a warrant [JURIST report] before using a criminal suspect’s cell phone data to track his movements. In July the US Court of Appeals for the Fifth Circuit ruled [JURIST report] that warrants were not required to track cell phones. In the same month the New Jersey Supreme Court ruled [JURIST report] that police must obtain search warrants before obtaining tracking information from cell phone providers, marking the first time a state supreme court had recognized a Fourth Amendment protection for cell phone location data. In May of last year the Florida Supreme Court ruled [JURIST report] that police need a warrant to search a defendant’s cell phone at the time of arrest.