California's Supreme Court has ruled that the police don't need a warrant to read text messages held on a suspect's phone.
The opinion was handed down during the trial of Gregory Diaz, arrested for drug dealing in 2007. On his arrest, the police found tabs of Ecstasy in his possession, along with a phone containing a suspicious text message that appeared to be agreeing a price.
Warrantless searches of 'persons, houses, papers, and effects' are permitted where they are 'incident to lawful arrest' - on the grounds that there's always a danger that the arrested person might try to conceal or destroy evidence.
"When carried in clothing (rather than inside luggage or a similar container), a mobile phone is personal property that is 'immediately associated with the person of the arrestee'," the judgement reads.
"Accordingly, under controlling high court decisions, police may, without obtaining a warrant, inspect a mobile phone carried by a suspect at the time of arrest, by viewing or listening to its electronically stored data, including text messages, even when a substantial time has elapsed since the arrest."
The decision was carried five-to-two. Justice Kathryn Mickle Werdegar dissented, saying it allowed the police "to rummage at leisure through the wealth of personal and business information that can be carried on a mobile phone or handheld computer merely because the device was taken from an arrestee's person."
Last September, a federal appeals court ruled that judges have the right to force the government to get a warrant before accessing cellphone location records.
And in June, the Supreme Court ruled that a police department had not violated an officer's privacy by reading text messages he had sent on a department-owned pager.