Killer is Loose (The) (1956)

Despite the perpetrators escaping with the money, milquetoast bank employee Leon Poole is seen in a more heroic light when he confronts the crooks in a robbery in progress. Later in apprehending Poole in discovering he was the inside person on the robbery, Police Detective Sam Wagner accidentally kills Poole's wife, Doris Poole, in the crossfire, she apparently a somewhat innocent bystander in not knowing about her husband's involvement in the crime until after the fact. Almost three years into his ten year prison sentence, he largely seen as a model prisoner, Poole is able to escape. Evidence indicates that Poole is that one in a thousand convict who truly meant it when he said that he would get back at Wagner. However, Wagner and his team are unaware what Poole intends is for Wagner to feel the same pain as him, Poole's intended target being Wagner's wife, Lila Wagner. The situation is made all the more difficult for the Wagners in their marital issue, namely Lila long having wanted her husband to give up the police life.