During one of the Winter Soldier's missions, a brainwashed Black Widow is brought into custody at S.H.I.E.L.D. headquarters. She had been influenced by old Russian brainwashing technology so it seemed she had broken free of one brainwashing attempt and had returned to her old self. This was actually a ruse by rogue Russian elements in order to strike at Nick Fury. Black Widow tried to kill Nick Fury but Sitwell got on the trajectory of the shot and was killed instead of Fury. His sacrifice gave Fury the opportunity to save himself.