A digital rights organization told the Oregon Supreme Court that allowing law enforcement officials to search arrestees' cell phones violates privacy protections guaranteed by the Constitution.

In the case Oregon v. Nix, police officers searched through the data on a criminal suspect's cell phone after he had been arrested and placed in a holding cell. The officers did not obtain a warrant for the search, claiming that the search was "incident to arrest," an exception to the warrant requirement that lets officers search for weapons or prevent evidence from being destroyed.

In an amicus brief [PDF] filed Friday, the Electronic Frontier Foundation argued that law enforcement officials should not be able to search the cell phone of a criminal suspect without a warrant.

"This is an empty excuse from the police -- the suspect was in custody and unable to destroy evidence on his cell phone," said EFF Senior Staff Attorney Marcia Hofmann. "The Fourth Amendment protects us from unreasonable intrusions by the police and ensures that a neutral magistrate decides when the police can search private information. There was no need for the police to sidestep the warrant process here. If courts give police the freedom to rummage through the cell phones of anyone they arrest, then the constitutional protection of the warrant process is meaningless."

In January, the California Supreme Court ruled 5 to 2 that police can search the cell phone of a person who's been arrested without obtaining a warrant and use data found on the device as evidence. The court said that when cell phones are an item on a person at the time of his or her arrest, police are entitled to inspect its contents without a warrant, just as they are allowed to search his or her clothing or wallet.

The EFF noted that privacy protections for searching through cell phones data was "critically important" because most devices contain highly personal information, such as pictures of your family and friends.

"Of course, criminal suspects could have information on their cell phones that might be of interest to police," Hofmann added. "When investigators have enough information to get a warrant, they should be able to search them."

"But judges should not allow a narrow exception to the warrant requirement to swallow the basic rule meant to protect everyone's privacy rights."