There is a startling amount of information available (and it's growing) concerning how exactly the FBI "catches" the terrorists they trot out on the 6 o'clock news. This video is a good introduction and launching point. If you dig far enough, you'll find that there's a lot of publicly available information about how the whole program is bullshit. Digging further, you'll find some interesting confirmed government conspiracies. Digging a bit more will land you in full-blown conspiracy-theory town.
For today, though, I just recommend watching this 10-minute video.