In recent months, both the FBI and the Homeland Security department have issued alerts to local police departments to watch out for suspicious bulk purchases of thousands of cheap prepaid cell phones. Those alerts in turn have triggered a spate of investigations and arrests — many of them later quietly dropped. Anti-terrorism officials fear, and have documented, the use of cell phones as bomb detonators in Madrid, Bali, Saudi Arabia, and Iraq, according to counter-terrorism expert Vincent Cannistraro. Full Story