A Secret Service agent who tried to shield former President John F. Kennedy from an assassin’s gunfire in 1963 died on Monday. Clint Hill, 93, died at his California home from unknown causes. He had been serving on presidential security detail for just three years when he made the move that defined his career.

Clint Hill, who was seen in film footage of the assassination scrambling across the back of the presidential limousine, died at his home. He was 93.