Discover
Bela Lugosi
Dr. Feodor Orloff / Prof. John Dearborn
Hugh Williams
Det. Insp. Larry Holt
Greta Gynt
Diana Stuart
Edmon Ryan
Lieutenant Patrick O'Reilly
Wilfred Walter
Blind Jake
Arthur E. Owen
Dumb Lou
Alexander Field
Fred Grogan
Gerald Pring
Henry Stuart
O.B. Clarence
Prof. John Dearborn (voice)
May Hallatt
Police Constable Griggs
Bryan Herbert
Police Sgt. Walsh
Charles Penrose
Morrison, undercover detective
Julie Suedo
Orloff's Secretary
Art
Duncan Sutherland
Art Direction
Crew
Jan Van Lusil
Additional Dialogue
Editing
Ted Richards
Editor
Writing
Edgar Wallace
Novel
Patrick Kirwan
Screenplay
Walter Summers
Screenplay
John Argyle
Screenplay