The United States Supreme Court recently issued a ruling holding that police are NOT permitted to search a person's cell phone incident to an arrest absent a warrant or a separate exigent circumstance.
The United States and Pennsylvania Constitutions protect against unreasonable search and seizure. The facts of the most recent case, Riley v. California, were: the police validly arrested an individual. Pursuant to the "search incident to arrest" exception to the warrant requirement, the police performed a pat down of the arrested individual. He was in possession of a cell phone. The police used the search incident to arrest exception to then look through the individual's cell phone, where the police found additional incriminating evidence.
The United States Supreme Court held that the search of the individual's cell phone was unconstitutional. Absent a search warrant, the police may only search an individual's phone after he has been arrested if the police can point to the existence of an exigent circumstance that would excuse a warrant. The police cannot extend the "search incident to arrest" exception to search a cell phone.