The Supreme Court Will Hear a Major Case on Cellphone Data Privacy
The U.S. Supreme Court on Monday agreed to hear a major case on privacy rights in the digital age that will determine whether police officers need warrants to access past cellphone location information kept by wireless carriers.
The justices agreed to hear an appeal brought by a man who was arrested in 2011 as part of an investigation into a string of armed robberies at Radio Shack and T-Mobile stores in the Detroit area over the preceding months. Police helped establish that the man, Timothy Carpenter, was near the scene of the crimes by securing cell site location information from his cellphone carrier.
At issue is whether failing to obtain a warrant violates a defendant’s right to be free from unreasonable searches and seizures under the U.S. Constitution’s Fourth Amendment.
The information that law enforcement agencies can obtain from wireless carriers shows which local cellphone towers users connect to at the time they make calls. Police can use historical data to determine if a suspect was in the vicinity of a crime scene or real-time data to track a suspect.
The legal fight has raised questions about how much companies protect the privacy rights of their customers. The big four wireless carriers, Verizon, AT&T, T-Mobile, and Sprint, receive tens of thousands of requests a year from law enforcement for what is known as “cell site location information,” or CSLI.
Get Data Sheet, Fortune’s daily tech newsletter.
Carpenter’s bid to suppress the evidence failed and he was convicted of six robbery counts. On appeal, the Cincinnati, Ohio-based 6th U.S. Circuit Court of Appeals upheld his convictions, finding that no warrant was required for the cellphone information.
Civil liberties lawyers say that police need “probable cause,” and therefore a warrant, in order to avoid constitutionally unreasonable searches.
But, based on a provision of a federal law called the Stored Communications Act, the government said it does not need probable cause to obtain customer records. Instead, the government said, prosecutors must show only that there are “reasonable grounds” for the records and that they are “relevant and material” to an investigation.
Civil liberties groups assert that the 1986 law did not anticipate the way mobile devices now contain a wealth of data on each user. Carpenter is represented by the American Civil Liberties Union.
The Supreme Court has twice in recent years ruled on major cases concerning how criminal law applies to new technology, on each occasion ruling against law enforcement. In 2012, the court held that a warrant is required to place a GPS tracking device on a vehicle. Two years later, the court said police need a warrant to search a cellphone that is seized during an arrest.