First, there's absolutely no evidence that Americans were in any way involved in this guy's abduction.
Second, He says that an American was present after he was tortured, but only found this out through one of his captors. So, it's basically the word of the kidnappers who abducted that you're relying upon, or the word of an Iranian journalist with an axe to grind.
Of course, when it comes to indicting America, that whole innocent until proven guilty thing goes out the window, doesn't it?