Kind of reminds me of that story some cops told of when they used a polygraph-lie detector on a suspect. The main problem is they didn't have one, so they took a photocopier and put a piece of paper with the word "LIE" on it in big bold letters in the scan plate. Then they brought in the suspect, told him it was a lie detector, and started questioning him. Everytime they thought he was lying, they hit the copy button. Even though this was a few years back, I still find it hard to believe the suspect was that stupid.
That was from one of the season's of The Wire.