Justice Dept. issues policy for phone surveillance technology; will generally require warrants

The Justice Department says federal law enforcement must now generally obtain search warrants before using secretive and intrusive cellphone technology.

The warrant requirement is part of a new policy unveiled Thursday regarding cell-site simulators, which can sweep up basic cellphone data from a neighborhood and help identify a suspect's location. There are some exemptions to getting a warrant, such as during an emergency.

The policy also requires deleting cellphone data that's been collected once law enforcement officials have the information that they need.

Still, it's unclear how broad an impact the policy will have, since it does not directly affect local law enforcement except when they're working alongside federal authorities.

Local police departments, including in Baltimore, have faced scrutiny over how they employ the technology.