Which country has the most to gain from the death of the IAEA inspector killed in car crash in Iran?

There's news coming out of Iran today that's tailor-made for conspiracy theories: According to The Associated Press,
officials have confirmed that an IAEA inspector has died and another
was severely injured in a car accident in central Iran. (Here's a report from the Iranian press
as well.) Think about it: Mysterious car crash? Check. Death of
inspector who worked at an agency which hasn't been on the best terms
with Iran? Check. The inspector's death comes ahead of talks between
the IAEA and Iran? Check.

The AP reports,
"The official news agency IRNA says the International Atomic Energy
Agency inspector died when the car in which he was riding overturned
around noon near a heavy water reactor being built in Khondab."

Details are scant and still coming in right now, but if you've been
paying attention to Iran's nuclear talks and compliance (or lack
thereof) with the United Nations and the International Atomic Energy
Agency, you'll know the two haven't been on the best of terms. Back in
February, Iran had shut out the IAEA from accessing its Parchin site, and back in March, the six world powers called upon Iran to allow access to its secret site. The AP adds,
"Tuesday's crash comes ahead of a new round of technical talks between
Tehran and the IAEA to be held in Vienna on May 13-14."