Boris Karloff

James Lee Wong

Grant Withers

Police Capt. Sam Street

Maxine Jennings

Myra Ross

Evelyn Brent

Olga Petroff / Countess Dubois / Sophie Dome

George Lloyd

Devlin

Lucien Prival

Anton Mohl

John St. Polis

Carl Roemer

William Gould

Theodore Meisle

Hooper Atchley

Christian Wilk

John Hamilton

Simon Dayton

Wilbur Mack

Russell

Lee Tung Foo

Tchin

Lynton Brent

Tommy

Grace Wood

Mrs. Roemer

Frank Bruno

Lescardi (uncredited)

Ed Cassidy

Ambulance Doctor (uncredited)

Wheaton Chambers

Chemistry Lab Director (uncredited)

Clancy Cooper

Warehouse Man (uncredited)

George DeNormand

John (uncredited)

Lester Dorr

Coroner (uncredited)

Herbert Evans

Wilk's Butler (uncredited)

Dick Reinhart

Dock Worker (uncredited)

William Nigh

Director

W.B. Eason

Asistente de Dirección

Hugh Wiley

Guión, Original Story

Houston Branch

Guión, Guión Adaptado

Harry Neumann

Director de Fotografía

Edward J. Kay

Compositor de la Música Original

Karl Zint

Recording Supervision

Abe Meyer

Music Director

William T. Lackey

Productor

Scott R. Dunlap

Productor, Production Manager

Monogram Pictures

Compañía de Produccion

Charles J. Bigelow

Production Manager

Gordon Bau

Maquilladora

Russell F. Schoengarth

Editor

Harry Grundstrum

Props

E.R. Hickson

Technical Supervisor