Bela Lugosi
Prof. Frederick Brenner aka Karl Wagner

John Archer
Richard Dennison

Wanda McKay
Judy Malvern

Tom Neal
Frankie Mills

Vince Barnett
Charley

Anna Hope
Mrs. Brenner

John Berkes
Fingers Dolan

J. Farrell MacDonald
Capt. Mitchell

Dave O'Brien
Det. Pete Crawford

Lucille Vance
Mrs. Malvern

Lew Kelly
Doc Brooks

Wheeler Oakman
"Trigger" Stratton

Ray Miller
The Big Tramp

George Eldredge
Det. Thompson (uncredited)

Eddie Kane
Police Chief Martin (uncredited)

Harry 'Snub' Pollard
Knocked-out Motorist (uncredited)

Bernard Gorcey
Shopkeeper (uncredited)

Willy Castello
Jeweler (uncredited)

Bob Reeves
Henchman (unconfirmed) (uncredited)

Walter McGrail
Coroner (uncredited)