Eraser(1996)

He will erase your past to protect your future.

John "The Eraser" Kruger is the top gun in the US Marshall Witness Protection Program; he protects witnesses by erasing their pasts. His latest assignment is whistle-blower Dr. Lee Cullen, who has evidence that her employer, a major arms corporation, is entangled in a conspiracy involving a high-tech railgun, but there is danger lurking closer to home for Kruger, from within his own department.