Tonton Streaming The Alfred Hitchcock Hour (1962) S1E15 - The Thirty First of February

Andrew Anderson is an advertising executive who discovers the body of his deadwife laying at the bottom of the basement stairs. An investigating detective named Sgt. Cresse believes Mr. Anderson is guilty of murder. He wants to trick him into making a confession by making Mr. Anderson believe that his wife is still alive and that she is having an affair with one of his fellow workers at the advertising agency. Eventually Mr. Anderson is proven innocent of murder, but Cresse's hounding has left him hopelessly insane.