In a unanimous ruling on Thursday, the New Jersey Supreme Court decided that police must get a warrant if they want to track a suspect using cellphone data, which grants NJ citizens more privacy protections than under federal law.
The measure, which will take effect in 30 days, mandates all law enforcement officers obtain a search warrant based on probable cause if they want to access someone's cellphone locating data. Since 2010, police have had to satisfy a lower standard of demonstrating there are "reasonable grounds" to believe the information would be relevant to an investigation, reports Times-Standard.
The ruling was based off a 2006 case in which police tracked Robert Earls, who they believed to be in danger, by using information provided by his cellphone provider, T-Mobile. Detectives not only found the suspect at a motel based on one of the location traces, but they also found stolen property and marijuana. Earls pled guilty to the charges, but was allowed to appeal a ruling on a motion to suppress the evidence collected that night, reports POLITICO.
Writing for the court, Chief Justice Stuart Rabner said that the prevalence of cell phones today only makes the privacy expectation more important.
"No one buys a cell phone to share detailed information about their whereabouts with the police. That was true in 2006 and is equally true today. Citizens have a legitimate privacy interest in such information," wrote Rabner.
"Disclosure of cell-phone location information, which cell-phone users must provide to receive service, can reveal a great deal of personal information about an individual. With increasing accuracy, cell phones can now trace our daily movements and disclose not only where individuals are located at a point in time but also ... with whom they choose to associate," Rabner continued.
"Yet people do not buy cell phones to serve as tracking devices or reasonably expect them to be used by the government in that way. We therefore find that individuals have a reasonable expectation of privacy in the location of their cell phones under the State Constitution."
The opinion will only apply to the defendant in the case decided and future cases.