From the Times: "Moussavi was first run over by a sport utility vehicle outside his home, Mr. Makhmalbaf wrote on his Web site. Five men then emerged from the car, and one of them shot Mr. Moussavi. Government officials took the body late Sunday and warned the family not to hold a funeral, Mr. Makhmalbaf wrote."
Now imagine this regime with nuclear weapons.
While I think Mr. Moussavi's death represents an escalation, we already know that the Iranian regime was brutal. Here's an interesting little factoid, though: The number of nuclear-armed brutal regimes who have never actually used their nuclear weapons is only every single one of them.