Jan Sterling and Gary Merrill in The Human Jungle (1954)

Danforth is assigned to take over the police department in a section of a large city saddled with juvenile delinquency, petty crimes, graft and also a recent unsolved murder of a strip-tease dancer. Recognizing the laxity of the department he implements many changes and soon finds himself under fire by the newspapers, the attorney of a racket leader and the denizens of this human jungle. He calls this a cop’s war that is the same as a soldier’s war with the difference being that people hate cops. His cause isn’t helped when a rookie policeman accidentally kills an innocent bystander. And he has to protect police informer Mary Abbott from Swados, a killer in the hire of the man behind the petty mobsters.