Philip 'Scotty' Grayson
Daniel F. O'Hara
Dr. Anastasia 'Toni' Neva
Dr. Ritter von Stolb
Igor Braun
Krebs
Dr. Frederick Townsend
Dr. William Forrest
Anton Radchek
Dr. Homer Allen
Carl Bemish
Narrator (voice)
Police Sergeant
FBI Chemist
Voice on Tape Recorder
Mr. North
Mrs. Ecko, the Landlady
FBI Agent Miller
Adolph Mizner
Police Detective Gaines
Feodore
FBI Agent Alison
FBI Agent Thompson
G.W. Hunter
