According to a long line of Supreme Court precedent, the police do not need a warrant to search the individuals they arrest, and that includes both the persons and possessions of the arrestees, including any bags, containers, or other items they were carrying. Furthermore, the police may conduct a warrantless search of the immediate vicinity around the arrest site. This exception is designed to help law enforcement prevent the destruction of evidence and to discover any evidence or weapons that might have been concealed.
The rise of the cell phone complicates this picture. Unlike diaries, notebooks, or briefcases, all of which the police are allowed to search incident to arrest, cell phones contain previously unimaginable amounts of personal information, including not only words and images but also GPS location data. In other words, should getting arrested for a minor offense like jaywalking be sufficient to allow the police virtually unlimited access to your private affairs in search of additional wrongdoing?
The lower courts are divided. In 2013, the California Supreme Court ruled against David Riley, letting the warrantless search of his cell phone stand. The U.S. Court of Appeals for the 1st Circuit, by contrast, ruled against the police that same year in the Boston case, adopting a “bright-line rule” 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” under any circumstances.