Boris Karloff
James Lee Wong
Acting
Grant Withers
Police Capt. Sam Street
Acting
Maxine Jennings
Myra Ross
Acting
Evelyn Brent
Olga Petroff / Countess Dubois / Sophie Dome
Acting
George Lloyd
Devlin
Acting
Lucien Prival
Anton Mohl
Acting
John St. Polis
Carl Roemer
Acting
William Gould
Theodore Meisle
Acting
Hooper Atchley
Christian Wilk
Acting
John Hamilton
Simon Dayton
Acting
Wilbur Mack
Russell
Acting
Lee Tung Foo
Tchin
Acting
Lynton Brent
Tommy
Acting
Grace Wood
Mrs. Roemer
Acting
Frank Bruno
Lescardi (uncredited)
Acting
Ed Cassidy
Ambulance Doctor (uncredited)
Acting
Wheaton Chambers
Chemistry Lab Director (uncredited)
Acting
Clancy Cooper
Warehouse Man (uncredited)
Acting
George DeNormand
John (uncredited)
Acting
Lester Dorr
Coroner (uncredited)
Acting
Herbert Evans
Wilk's Butler (uncredited)
Acting
Dick Reinhart
Dock Worker (uncredited)
Acting