Nothing like sounding a little guilty.
The United States has denied any role in Wednesday's killing of an Iranian nuclear scientist in Tehran.
After the State Department initially declined to respond to Iranian charges that the U.S. or Israel was responsible for Mostafa Ahmadi Roshan's assassination, the White House said the United States "had absolutely nothing to do" with the blast that killed Roshan. White House spokesman Tommy Vietor said the U.S. strongly condemns the attack and all acts of violence.
U.S. Secretary of State Hillary Clinton repeated the White House denial of any U.S. involvement in the scientist's killing. "I want to categorically deny any United States involvement in any kind of act of violence inside Iran," she said.