Danger Signal.

Ronnie Mason steals a dead woman's wedding ring and money and leaves a fake suicide note. The woman's husband, Thomas Turner, believes his dead wife might have been seeing Mason behind his back. Mason leaves town, changes his name to Marsh and rents a room in the house of public stenographer Hilda Fenchurch and her younger sister Anne. She plots to lure Marsh to a beach house and poison him, but when Marsh runs off, he is surprised by Thomas Turner and plunges off a steep cliff to his death.