A U.S. Department of Homeland Security (DHS) unmanned aerial vehicle has crashed off the coast of southern California. Customs and Border Protection said the drone was being flown on a border security mission when a mechanical problem developed about 30 kilometers southwest of San Diego. Spokesman Mike Friel said the crew operating the drone from Texas decided to crash it in the Pacific Ocean. The $18 million Predator B surveillance drone was one of 10 that DHS uses to patrol the border with Mexico, and it was one of two drones equipped with radar specifically designed to be used over the ocean.