Cell phones store more data than ever before, something which has led privacy advocates to argue against police searches without warrants. Sean Gallup/Getty Images

The Supreme Court has agreed to decide whether police need a warrant to search the cellphones of people they have arrested.

Justices said Friday they will hear appeals in two cases in which criminal defendants were convicted and sentenced at least in part on the strength of evidence obtained by warrantless searches of their cellphones.

At issue is a 40-year-old high court ruling allowing warrantless searches of items people are carrying when they are arrested. Lower federal and state courts have differed over whether the ruling should apply to increasingly sophisticated cellphones and smartphones.

The two cases the Supreme Court will hear are Riley v. California, and U.S. v. Wurie.

The Riley case arose after gang member David Leon Riley was arrested in connection with a shooting of a rival gang member. Police arrested Riley and subsequently searched his cellphone, where they found information about Riley’s gang affiliations and the contact information of other suspected gang members.

The Wurie case is based on an arrest where the police found information on Brima Wurie’s phone about an address where they later made separate arrest.

While courts commonly agree that most objects found on a suspect can be searched after an arrest, cellphones are controversial because of the amount of personal, indentifying data they may include.

That’s led privacy organizations to come out strongly against the ability of police to search cellphones along with other objects after an arrest.

“The information contained in cellphones is often highly personal and may not have any connection to the reason for the arrest,” the Electronic Privacy Information Center wrote in a statement about the Riley case. Allowing police to search cellphones after an arrest, “would permit police to search the entirety of an arrestee's digital life. Such data may also contain communications and information from innocent third parties, whose privacy interests are also implicated.”

Experts say deciding the constitutionality of cellphone searches is growing more important by the day as people store more and more data about their lives on their smartphones.

Despite the controversy surrounding the searches, however, three appellate courts have upheld warrantless phone searches in the past.

California passed a law in 2011 that would require police to obtain a warrant to search cellphones after an arrest, but Gov. Jerry Brown overturned the law.

The Supreme Court cases will be argued in April and decided by late June.

Al Jazeera and wire services