Danger Signal

Danger Signal is a 1945 film noir starring Faye Emerson and Zachary Scott. It was adapted from the novel of the same name by Phyllis Bottome.

Mason leaves town, changes his name to Marsh and, using a limp he acquired jumping from the dead womans bedroom window and a veterans pin he steals from a fellow passenger on the L.A. bus, passes himself off as a wounded soldier and rents a room in the house of public stenographer Hilda Fenchurch and her younger sister Anne. To the consternation of professor Andrew Lang, who secretly loves Hilda, she falls for Marsh, the new tenant.The scheming Marsh learns that it is Anne who might inherit a great deal of money, so he suddenly switches his affections toward her. Hilda is jealous and suspicious. She plots to lure Marsh to a beach house and poison him. She isnt able to go through with it, but when Marsh runs off, he is surprised by Thomas Turner and plunges off a steep cliff to his death. ........

Source: Wikipedia