The Wall Street Journal reports: The Justice Department is scooping up data from thousands of mobile phones through devices deployed on airplanes that mimic cellphone towers, a high-tech hunt for criminal suspects that is snagging a large number of innocent Americans, according to people familiar with the operations.

The U.S. Marshals Service program, which became fully functional around 2007, operates Cessna aircraft from at least five metropolitan-area airports, with a flying range covering most of the U.S. population, according to people familiar with the program.

Planes are equipped with devices—some known as “dirtboxes” to law-enforcement officials because of the initials of the Boeing Co. unit that produces them—which mimic cell towers of large telecommunications firms and trick cellphones into reporting their unique registration information. [Continue reading…]