Check out this episode of This American Life,"The Convert" "In 2006, a new convert showed up at a mosque in Orange County, California, eager to study the Koran and make new friends. But when he started acting odd and saying strange things, those friends got suspicious. To them, he was Farouk al-Aziz. But his real name was Craig Monteilh, and he was working undercover for the FBI. (Read the update to this story here.)"