The Massachusetts Supreme Judicial Court has ruled that police need a warrant to obtain cellphone location data to track a suspect for more than a brief time period.

The Court based its ruling on protections from unreasonable searches and seizures in the state constitution.  How Appealing links to the opinion.  The ruling is the second by a state supreme court to require a warrant.  The New Jersey Supreme Court was the first state supreme court to afford constitutional protection to cell phone records.

The Massachusetts court ruled 5-2 in the case of Shabazz Augustine, who was arrested based on data showing his location when his girlfriend was killed.  The court noted that police had obtained two weeks of data by persuading a court the information was relevant and material to an ongoing probe.

Because police obtained two weeks’ of data, a search warrant supported by probable cause was required, the court said.  “The tracking of the defendant’s movements in the urban Boston area for two weeks was more than sufficient to intrude upon the defendant’s expectation of privacy” safeguarded by  the Massachusetts Commonwealth’s  constitution, the majority opinion held.