Local, state and federal law enforcement authorities made more than 1.3 million demands for cellphone subscriber information last year in a sign of their growing reliance on technology to aid criminal and emergency investigations. The reports from carriers came in response to a congressional inquiry seeking to document the surge in surveillance involving data from mobile devices, as more and more Americans carry cellphones to talk, text and send messages. Rep. Edward J. Markey (D-Mass.) requested the information from carriers, including records on “cell tower” dumps, in which the carriers provide law enforcement authorities with data on cellphone users near a cell tower during a discreet period of time. Read the full story at The Washington Post.