Philip 'Scotty' Grayson
Louis Hayward
Daniel F. O'Hara
Dennis O'Keefe
Carl Bemish
Frank Ferguson
Narrator (voice)
Reed Hadley
Police Sergeant
Ray Teal
FBI Chemist
William Tannen
Voice on Tape Recorder
Gale Storm
Mr. North
Arthur Space
Mrs. Ecko, the Landlady
Tamara Shayne
FBI Agent Miller
Keith Richards
Adolph Mizner
Grandon Rhodes
Police Detective Gaines
Steve Pendleton
Dr. Anastasia 'Toni' Neva
Louise Allbritton
Feodore
Howard Negley
FBI Agent Alison
Jimmy Lloyd
FBI Agent Thompson
Myron Healey
G.W. Hunter
John Hamilton
Paul Bryar
Fred Coby
Bert Davidson
Marten Lamont
Lee Phelps
Suzanne Ridgway
Dr. Ritter von Stolb
Carl Esmond
Arthur Tovey
Crane Whitley
Igor Braun
Onslow Stevens
Krebs
Raymond Burr
Dr. Frederick Townsend
Art Baker
Dr. William Forrest
Lowell Gilmore
Anton Radchek
Philip Van Zandt
Dr. Homer Allen
Charles Evans
Director
Gordon Douglas
Screenplay
George Bruce
Story
Bertram Millhauser
Producer
Grant Whytock
Director of Photography
George Robinson
Unit Manager
Joseph Small
Art Direction
Rudolph Sternad
Camera Operator
Edward Colman
Script Supervisor
Dorothy B. Cormack
Wardrobe Supervisor
Edward P. Lambert
Sound
John R. Carter
Edward Small
Makeup Artist
Norbert A. Myles
Editor
James E. Newcom
Set Decoration
Howard Bristol
Still Photographer
Ken Lobben
Hairstylist
Margaret Martin
Original Music Composer
Paul Sawtell
Grip
William Dalton
Assistant Director
Ridgeway Callow