The Prowler (1951 film)
The Prowler is a 1952 black-and-white thriller film noir directed by Joseph Losey that stars Van Heflin and Evelyn Keyes. The film was produced by Sam Spiegel (as S.P. Eagle) and was written by Dalton Trumbo under a pseudonym.
Plot
Webb Garwood (Van Heflin), a disgruntled cop, is called to investigate a voyeur by Susan Gilvray (Evelyn Keyes). Her husband works nights as an overnight radio personality. Webb falls in love with the young and attractive married woman.
Obsessed, he woos her despite her initial reluctance and the two begin an adulterous affair. Webb finds out about an insurance policy on the husband's life. He dreams up a scheme in which a phantom "prowler" would be a good scapegoat if Susan's husband should happen to die mysteriously. After becoming a prowler himself, Webb "investigates" and then commits the murder, making it look like a tragic accident with he and the husband shooting at each other as each suspected the other of being the prowler. Webb's ruse fools a coroner's jury, thanks in part to both Susan and Webb testifying that they didn't know each other prior to her husband's death. Susan initially suspects Webb of foul play, but becomes convinced of his innocence and subsequently marries him.