A few years later, a friend of Theimer's wife casually mentioned that 9/11 "was an inside job." Theimer was livid and turned to the Internet, to prove the friend wrong.

The websites, the books and the documentaries he saw online persuaded him. He was wrong, and so was the system.

"I was duped," Theimer said. "It really hurt. I cried. I couldn't sleep for months."