Richard O'Sullivan

Roger Court

Alida Valli

Roberta Gleukovitch

Eduardo Ciannelli

Dr. Vivaldi

Trevor Howard

Major Roger Court

Richard Basehart

Joe Hamstringer

Stephen Murray

British Consul in Venice

Arnoldo Foà

Commissioner

Guido Celano

Chief Constable

Helen Goss

Undetermined Role

Giorgio Costantini

Pescovitch

Angelo Cecchelin

Luza

Nino Vechina

First Killer

Armando Papette

Second Killer

Giovanni Karuz

Third Killer

Joan Butterfield

Mrs. Harrington

Mario Soldati