The DUP Security Cameras are the bigger cameras you will find, usually surrounding the area where the Mobile Command is located. They show up as a camera icon on your map (not the icon in the square, but by itself) and when you get within their range, you will hear an annoying siren and the camera icon will flash red.
The Security Cameras are programmed to detect known Bioterrorists and warn the DUP whenever they get into range. The cameras themselves are large enough to be able to recognize them and a few shots from any of the powers will quickly destroy them.