"Officers use "Stingrays" to mimic a cell phone tower and intercept information from phones in a whole neighborhood. The federal government and police have kept such devices under wraps for years.
Now a question about the way police do their jobs. When is it OK for them to keep secrets about the tools they use - tools that can spy on us? That's being asked more and more in connection to something called IMSI catcher. And IMSI catcher is a device that police use to intercept cell phone signals, and as NPR's Martin Kaste reports, the police would rather keep the devices out of the public eye."