The U.S. Supreme Court has agreed to hear a case centered on whether government agencies, including law enforcement, should be required to get a warrant before obtaining cell phone location records.

The case, Carpenter v. United States, goes back several years to a string of armed robberies at various cell phone stores in and around Detroit. To catch the criminals, the government sought and obtained the historical cell phone location data of private individuals, using the phones' location data to track the suspects' movement at multiple points each day.

The primary suspect in the case, Timothy Carpenter, was a customer of MetroPCS Inc., now owned by T-Mobile US Inc. The government requested more than 100 days of data from the operator, and MetroPCS complied, providing 186 pages of Carpenter's cell phone records, according to case documents from the American Civil Liberties Union.

In addition, the government issued a separate order requesting records from Sprint Corp., for those times when Carpenter's phone was roaming on Sprint's network in areas where MetroPCS did not have coverage. Sprint produced two pages of call detail records, according to the case documents, and both companies also produced lists of their cell sites in southern Michigan and northwestern Ohio.

Notably, the government had not obtained a warrant before getting these records, having instead relied on a disclosure order under the Stored Communications Act, a law that covers how and when the government can compel a communications service provider to disclose "stored wire and electronic communications and transactional records."

Carpenter and his brother were ultimately convicted in the case based in part on the cell phone location evidence.

Following the ruling, they appealed, with the ACLU arguing as part of the appeal that the government had violated the Fourth Amendment when it obtained the location records from the defendants' wireless carriers without a warrant. The Fourth Amendment protects citizens against unreasonable searches and seizures and also requires that probable cause be established before the issuance of a warrant.

The appeal was initially heard by the Sixth Circuit Court of Appeals, which in a divided ruling, sided with the government, finding that no warrant was required under the Fourth Amendment. The ACLU petitioned the U.S. Supreme Court to take on the case, saying the question the court must ultimately answer is a constitutional one. Specifically, the question is "whether the warrantless seizure and search of historical cell phone records revealing the location and movements of a cell phone user over the course of 127 days is permitted by the Fourth Amendment."

On June 5, the court granted the petition, meaning it will hear the case.