Nobody (1927)

When financier John Rossmore is found murdered in his library, suspicion points to his butler Hedges, who was instrumental in obtaining his divorce. At the trial, when the jury retires, Tom Smith, a young businessman who has sworn he does not know Rossmore, holds out for acquittal and tells his story to the jurors: While he and his wife are vacationing in Palm Beach, Rossmore is attracted to Little Mrs. Smith, and the Smiths are invited on a yachting trip. After Tom is recalled to New York on business, Rossmore drugs Mrs. Smith and seduces her, offering blackmail for her silence. Terror-stricken, she goes to Rossmore's home, enters with a key given her, and shoots him. The jurors agree never to divulge the story, and they acquit the butler.