Unmasked (1950)

The editor of a sleazy tabloid newspaper has been borrowing money from his lover, the wife of a rich theatrical producer, and promises to marry her when she gets a divorce. However, the husband refuses to grant her a divorce, and takes back all the money and jewelry he has given her. The editor sees her husband leaving her apartment and, seeing his opportunity, kills her, takes all his IOUs (and the jewelry) and frames the husband for the murder.