The U.S. Supreme Court on Friday agreed to decide if warrantless police searches of the contents of cellphones violate the Constitution.

The justices granted review in two closely watched cases: Riley v. California, 13-132, stemming from a decision by the California Court of Appeal, and U.S. v. Wurie, 13-212, an appeal from a decision by the U.S. Court of Appeals for the First Circuit.

David Leon Riley’s case arose from a police stop in 2009 because he was driving with expired tags. His car was impounded by the police after they discovered he also was driving with a suspended license. During an inventory search of his car by police, concealed weapons were discovered. Riley was arrested and his smartphone was confiscated.

The phone was a Samsung Instinct M800 “smartphone”—a touch-screen device designed to compete with Apple’s iPhone, capable of accessing the Internet, capturing photos and videos, and storing both voice and text messages, among other functions.

During two separate warrantless searches of Riley’s phone, the police discovered evidence of his connection to a gang and to a recent gang shooting. He was convicted for his role in the gang shooting.

On appeal, he argued that the cell phone search violated the Fourth Amendment’s ban on reasonable searches and seizures. The California Court of Appeals affirmed his conviction, and the state’s highest court declined to review his case.

Riley’s high court counsel, Jeffrey Fisher of Stanford Law School, had urged the justices to grant review, writing in the petition for certiorari: “Federal courts of appeals and state courts of last resort are openly and intractably divided over whether the Fourth Amendment permits the police to search the digital contents of an arrestee’s cell phone incident to arrest. This issue is manifestly significant.”

The justices rewrote the question presented for review by Riley, saying they would decide whether the evidence admitted in his trial was obtained in a search of his cell phone that violated his Fourth Amendment rights.

Riley is one of the most important constitutional privacy cases the Court has heard in years, and could prove to be one of this term’s blockbusters,” said Elizabeth Wydra, chief counsel to the Constitutional Accountability Center, which had filed an amicus brief supporting Riley.

The other case that the justices agreed to hear involves the less-sophisticated cell phone of Brian Wurie, who was arrested in connection with a drug sale in the parking lot of a Boston convenience store. While at the police station, officers noticed that on the external screen of Wurie’s Verizon LG flip phone were multiple calls from one number identified as “my house.”

The officers went to the phone’s call log, took down the number, and used a reverse phone directory to obtain the address. They then went to the address and, after obtaining a warrant, found 215 grams of crack cocaine. Wurie was convicted and sentenced to 262 months in prison.

A divided panel of the First Circuit vacated Wurie’s conviction, ruling that “the search-incident-to-arrest exception does not authorize the warrantless search of data on a cell phone seized from an arrestee’s person” in any circumstances.

The United States, in its petition, contends the First Circuit decision cannot be squared with two prior Supreme Court decisions which establish an across-the-board rule that the police may search any items found on the person of an arrestee so long as the search is not conducted in an unreasonable manner.

The justices said they would decide if the Fourth Amendment permits the police, without obtaining a warrant, to review the call log of a cell phone found on a person who has been lawfully arrested.

Wurie’s high court counsel is Judith Mizner of the Boston Federal Public Defender Office.

The new cases will be argued during the court’s April session, beginning April 21.