The U.S. Supreme Court today made an important decision regarding police and cellphone data.

In its 5-4 ruling, the Supreme Court decided that police need a warrant to get access to user location data from wireless carriers. Getting that data without a warrant is an unreasonable search and seizure under the Fourth Amendment, said the Supreme Court.

The decision came as a result of a case involving a man named Timothy Carpenter who was convicted of multiple armed robberies. Police were able to deterine that Carpenter was near the robberies by getting his cell site location info from his carrier without a warrant.

"We decline to grant the state unrestricted access to a wireless carrier’s database of physical location information," said Chief Justice John Roberts.

Now that the Supreme Court has made this decision, Carpenter's case will go back to the lower courts, but it's said that his conviction may not be overturned because of other evidence in the case. Still, this is a major ruling that's sure to come up again in future cases.