E.A. Dupont Director Roscoe Karns Sgt. Heath Actor Grant Richards Philo Vance Actor Helen Burgess Ada Greene Actor Ruth Coleman Sibella Greene Actor Elizabeth Patterson Mrs. Tobias Greene Actor Harvey Stephens Dr. Von Blon Actor June Martel Barton Actor Ellen Drew Secretary Actor Frank Partos Screenwriter Gladys Unger Screenwriter Harry Fischbeck Cinematographer James Smith Film Editing Hans Dreier Art Director A. Earl Hedrick Art Director