Joachim Fuchsberger as Inspektor Higgins

Siw Mattson as Peggy Ward

Hubert von Meyerinck as Sir Arthur

Wolfgang Kieling as Sir Cecil

Pinkas Braun as Der Fremde

Claude Farell as Adela

Peter Mosbacher as Ramiro

Siegfried Rauch as Dr. Brand

Otto Stern as Mr. Merryl

Lill Lindfors as Sabrina

Renate Grosser as Mrs. Potter

Hans Krull as Mr. Potter

Ilse Pagé as Miss Finley

Edith Schneider as Professor Bound

Wolfgang Spier as Bannister

Ewa Strömberg as Library Clerk

Jimmy Powell as Casper

Eva Ebner as Secretary

Thomas Danneberg as Captain