The state’s highest court ruled today that law enforcement must generally obtain a search warrant before acquiring a criminal suspect’s cell-phone data in order to track his movements.

The Supreme Judicial Court, ruling in a case with echoes of the controversy over the National Security Agency’s surveillance programs, said a warrant is required under the Massachusetts constitution protections against unreasonable search and seizure.

“It’s an enormous victory for everybody in Massachusetts who cares about privacy,’’ said Matthew Segal, legal director of the American Civil Liberties Union of Massachusetts, which served as appellate counsel for the suspect in the case, Shabazz Augustine, who was being investigated in the 2004 homicide of his girlfriend, Julaine Jules of Malden.


Augustine was arrested after police used his cell-phone records to determine his whereabouts around the time of the killing. Authorities at that time relied on a federal law that only requires such files must be relevant to an investigation to get Augustine’s records from wireless carrier Sprint.

At that time, in 2004, the issue of data privacy was in its infant stage. It was common for many law enforcement investigators to use the federal law, the Stored Communications Act, to obtain similar records without a search warrant. Even the Massachusetts court acknowledged there was no guidance back then from judges that such searches were barred by the state constitution.

But in 2013, Augustine’s lawyers convinced a Suffolk County Superior Court judge to throw out on the evidence on the grounds that investigators should have obtained a search warrant for the cell-phone records, which would have required a judge to find probable cause the subject had committed a crime. Otherwise, they said, such a search violated Article 14 of the Massachusetts Constitution, which bars unreasonable searches and seizures

State authorities appealed the judge’s ruling, arguing that the records in question were not Augustine’s, but rather the property of his cell-phone company, Sprint, and that he should not have any expectation of privacy over them. Separately prosecutors argued that the affidavit they used to obtain the records under federal law had enough evidence to get a search warrant from a state judge, as well.


In 5-2 ruling issued Tuesday, the state’s highest court clarified the issues, providing both a clear definition of the privacy of phone records in the digital age, and also affording prosecutors a road map to using those records in their case against Augustine.

The court said it was possible that if the data covered only a short period, then obtaining the records under the federal Stored Communications Act without a search warrant might be acceptable. But it said it was clear that in Augustine’s case, in which two weeks of data was obtained, the period was too long.

“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,’’ said the Massachusetts court opinion, written by Justice Margot Botsford.

The ruling also makes Massachusetts the latest of several US states to set stricter limits on government access to citizens’ phone records.

“In holding here that the Commonwealth generally must obtain a warrant before acquiring a person’s historical [cellphone location] records, this opinion clearly announces a new rule,’’ Botsford added.

The court returned the case to the lower court, , where it will allow the Suffolk County District Attorney to argue that the original affidavit from 2004 met was strong enough anyway to get a search warrant for Augustine’s records. If so, the records could still be used at trial.

“We expect to prove that the affidavit submitted in 2004 would just as easily have supported a search warrant,’’ said Jake Wark, a spokesman for the Suffolk County District Attorney.


In addition, Wark said Suffolk prosecutors routinely obtain a search warrant to get cell-phone data, and that no other case would likely be affected by the state court’s ruling.