Nuclear scientist Shahram Amiri got a heroes welcome in Tehran, Iran, after claims he was captured by the U.S.

He said he was kidnapped and tortured by the Central Intelligence Agency, but U.S. officials said it's not true, that he defected to the U.S. as a willing informant.

"This happens all the time. Defectors come across, they think it is a good idea, they get paid a lot of money, and once the boredom sets in, the loneliness, they realize it's a huge mistake," former CIA Agent Bob Baer said.

The Washington Post reports Amiri was paid $5 million to provide intelligence on Iran's nuclear program, but he does not get to keep it since he returned to Iran.