George Murphy

Inspector James 'Jim' Belden

Finlay Currie

Professor Albert Kafer

Virginia Gilmore

Millie / Teresa Zalenko

Karl Stepanek

Alexi Laschenkov / Gregory Anders

Louisa Horton

Mrs. Elaine Wilben

Peter Capell

Chris Zalenko / Gino

Bruno Wick

Luther Danzig

Vilma Kurer

Mrs. Rita Foss

Ann Thomas

Philadelphia Suspect

George Roy Hill

Nicholas Wilben

Karl Weber

FBI Agent Charlie Reynolds

Michael Garrett

Michael Dorndoff aka Frank Torrance

Lotte Palfi Andor

Anna Kafer

Ernest Graves

Robert Martin

Robert Carroll

Boldany

Wolfgang Zilzer

August Helmuth

Bradford Hatton

Harry Mason

Rosemary Pettit

Mrs. Martin

Eva Condon

Landlady

Steve Mitchell

Samson

John Farrell

Taxi Driver (uncredited)

Nancy Hale

Mrs. Belden (uncredited)

Westbrook Van Voorhis

Narrator (voice) (uncredited)

Mary Young

Old Lady (uncredited)

Suzanne Moulton

Sherry Belden (uncredited)