Assuming this story is true, I'd be concerned that this is an attempt to draw the US Government into a confrontation that will help the hard-liners in Iran. As for who would want such a thing.
Clearly the hard-liners would like to try, once again, to get people to rally behind them in the face of "the great satan." You'd also have to look at the US Neocons, many of whom would like to remove any sympathy for Iran or Iranians that gets in the way of their long-disgraced axis-of-evil BS. And then there is Israel. At least some in Israel are on the same page as the neocons, though I wouldn't want to suggest that their position is universally held.
Anyway, I'm suspicious of the motives of anyone who wants to use this as anything but a reason to get the cops and/or FBI on the case.