Louis Hayward

Philip 'Scotty' Grayson

Acting

Dennis O'Keefe

Daniel F. O'Hara

Acting

Louise Allbritton

Dr. Anastasia 'Toni' Neva

Acting

Carl Esmond

Dr. Ritter von Stolb

Acting

Onslow Stevens

Igor Braun

Acting

Raymond Burr

Krebs

Acting

Art Baker

Dr. Frederick Townsend

Acting

Lowell Gilmore

Dr. William Forrest

Acting

Philip Van Zandt

Anton Radchek

Acting

Charles Evans

Dr. Homer Allen

Acting

Frank Ferguson

Carl Bemish

Acting

Reed Hadley

Narrator (voice)

Acting

Ray Teal

Police Sergeant

Acting

William Tannen

FBI Chemist

Acting

Gale Storm

Voice on Tape Recorder

Acting

Arthur Space

Mr. North

Acting

Tamara Shayne

Mrs. Ecko, the Landlady

Acting

Keith Richards

FBI Agent Miller

Acting

Grandon Rhodes

Adolph Mizner

Acting

Steve Pendleton

Police Detective Gaines

Acting

Howard Negley

Feodore

Acting

Jimmy Lloyd

FBI Agent Alison

Acting

Myron Healey

FBI Agent Thompson

Acting

John Hamilton

G.W. Hunter

Acting

Paul Bryar

Acting

Fred Coby

Acting

Bert Davidson

Acting

Marten Lamont

Acting

Lee Phelps

Acting

Suzanne Ridgway

Acting

Arthur Tovey

Acting

Crane Whitley

Acting