Who's Catching Your Cellphone Conversations?

With the right equipment, people can hijack your cellphone, listen to your calls and read your texts, alarming privacy rights advocates and tech experts alike. We know the eavesdropping is happening, but we don't know much about who's doing the listening.

The police and other law enforcement agencies do it, but they have been restricted by the FBI from telling us about it. Beyond the police, the listeners could be the U.S. government, corporate spies or even foreign intelligence agencies. The devices, known as IMSI catchers or by a brand name, Stingray, used to be expensive, bulky and hard to purchase. Now they can be bought online for as little as $1,800 and can be as small as a briefcase.