G.I. Joe: The Rise of Cobra

File cards and intel are items you find scattered throughout each mission in each respective section of the game. You can see a total for each mission at the Mission Select screen. File cards, contacts, and intel are easy to find and are usually sitting in plain sight in a corner somewhere. Each mission has at least one ability door that can only be opened by a certain type of character (Combat, Commando or Heavy). There are usually 2-4 intel/file cards per level.

See here for a full location Guide, courtesy of Jerry Appleby: LINK