George Murphy as Inspector James 'Jim' Belden

Finlay Currie as Professor Albert Kafer

Virginia Gilmore as Millie / Teresa Zalenko

Karl Stepanek as Alexi Laschenkov / Gregory Anders

Louisa Horton as Mrs. Elaine Wilben

Peter Capell as Chris Zalenko / Gino

Bruno Wick as Luther Danzig

Vilma Kurer as Mrs. Rita Foss

Ann Thomas as Philadelphia Suspect

George Roy Hill as Nicholas Wilben

Karl Weber as FBI Agent Charlie Reynolds

Michael Garrett as Michael Dorndoff aka Frank Torrance

Lotte Palfi Andor as Anna Kafer

Ernest Graves as Robert Martin

Robert Carroll as Boldany

Wolfgang Zilzer as August Helmuth

Bradford Hatton as Harry Mason

Rosemary Pettit as Mrs. Martin

Eva Condon as Landlady

Steve Mitchell as Samson

John Farrell as

Nancy Hale as

Westbrook Van Voorhis as

Mary Young as