The Killer Is Loose (1956)

"He was no ordinary killer... She was no ordinary victim... This is no ordinary motion picture!"

A savings-and-loan bank is robbed; later, a police wiretap identifies meek bank teller Leon Poole as the inside man. In capturing him, detective Sam Wagner accidentally kills Poole's young wife, and at his trial Poole swears vengeance against Wagner. Poole begins his plans to get revenge when he escapes his captors.