California police criticized for 'stingray' cellphone trackers

Law enforcement agencies in California are using devices that mimic cellular base stations to track mobile users, public records have revealed, triggering charges that the practice may be unconstitutional.
Agencies in Los Angeles, San Diego, San Jose, San Francisco, Sacramento and other areas own or have funding to buy the so-called “stingray” devices, according to documents uncovered in an investigation by TV station Sacramento News 10. The American Civil Liberties Union of Northern California highlighted the findings in a blog post on Thursday, saying the use of stingrays may violate constitutional restraints on searches.
Stingrays, which have been reported in use in Florida, Colorado and other states, are small portable devices that appear to nearby phones as if they are real cellular base stations. When a stingray is nearby, phones will automatically connect to it as if it were the nearest cell tower. Law enforcement most commonly uses the devices to track the location of phones, though there are stingrays that can monitor calls, Staff Attorney Linda Lye wrote in the blog post.