It's a scary time to be an Iranian nuclear scientist. Gunmen shot physicist Dariush Rezai in a motorcycle drive-by, Iranian news reported. Rezai was associated with Iran's Atomic Energy Organization, which oversees nuclear installations and uranium enrichment. Rezai was shot outside his home, near the Imam Ali military base, a secretive and secure Revolutionary Guard compound. Iran blamed the U.S. and Israel for the November 2010 killing of two nuclear scientists.