I knew a guy in high school. Nice guy, good sense of humor. A while ago, I was watching South Park. Around episode 201, a threat was sent to the makers of South Park, saying that if they release the episode, they could become like "Theo Van Gogh." This led to the episode being censored with loud bleeps. Later, he was arrested for attempting to join a muslim terror group. Apparently he went to the same high school as I did.
After a quick look in my year book, I confirmed that I knew him and sat next to him in high school.
It was profound. He seemed like the last person who could join a religion. But he changed. Then again, I never knew him that well to know how much he changed. It's just strange who the people you know can change into.