Backfire (1961)

STAKEOUT FOR A KILLER They were tough, ambitious cops, Marty Donovan and Tony Alfieri, a good precinct team. They agreed on most things except dames. Tony chased anything in skirts and Marty hated the look on Lenore Alfieri's face every time her husband cheated. Hated it enough to fall in love with her himself. Then Lenore dreamed up the stakeout-the unauthorized stakeout to catch the murderous jewel thief who was baffling Headquarters. No one could tell that it would end with Tony bleeding his life away on the jewelry shop floor while his killer escaped. Marty was caught in a squeeze. He had to build a cover of deceit and lies to protect Lenore and save his badge.