The "defected" Iranian nuclear scientist Shahram Amiri has reportedly turned up at the Iranian Interests Section in Washington DC. This is a saga that gets funnier by the minute and I'm sure there's a political comedy there.
Shahram Amiri was never really the big shot nuclear defector he was portrayed as the media and didn't really have much to say about IRan's nuclear program. The reports that he disclosed the Qom facility were nonsense because the Western intelligence sources said they knew about it months before his defection. He didn't even work in nuclear energy programs and his area of expertise unrelated to nuclear power. The closest connection that the media could make between him and the nuclear program in Iran was that he was employed at a university that had connections with the Iranian defense industry (as do most universities) including the Revolutionary Guards, who supposedly runs the nuclear energy program (a highly questionable claim itself.)
So I am speculating -- totally speculating -- that Amiri just wanted to go to the US and saw an opportunity by trying to "defect" instead of trying to get a visa like all the Iranians who visit the US. The US authorities realized that he had no real intelligence value, but had potential PR value because they could then cook-up all sorts of false claims about Iran's nuclear program and attribute it to this "defecting nuclear scientist." SOmewhere along the line, either Amiri decided that the US wasn't all he had hoped, or the US authorities realized that Amiri didn't really carry as much credibility as they had hoped, and so the relationship fell apart. Now, Amiri wants to go back to Iran, and the only way he can do is is to claim that he had been coerced into coming to the US in the first place.
This is again, just speculation on my part.