Calificación
Reparto

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