State police departments using cell-phone trackers

Sacramento's News10 has come out with a major study of police-department uses of so-called "stingray" devices to monitor cell-phone conversations. San Diego is among many California law-enforcement agencies using the devices.

When a stingray is close, phones will automatically connect to it as if it were a cell tower, according to PC World.

The American Civil Liberties Union (ACLU) is concerned that the stingrays collect information about third parties, not only the targets of investigation. This could be a violation of the Fourth Amendment, the ACLU believes.