Post Office Box 1001

Barcelona, Spain. A young man is murdered in the middle of the street in front of the police headquarters. Miguel and Marcial, two agents of the Criminal Brigade in charge of the investigation, find in the victim's room a newspaper where a cryptic classified ad appears.

• Julio SalvadorDirector
• Antonio Isasi-IsasmendiScreenplay
• Julio CollScreenplay
• Ramón FerrésOriginal Music Composer

• Conrado San MartínMiguel
• Elena EspejoCarmen
• Tomás BlancoAntonio
• Manuel de JuanMarcial
• Luis Pérez de LeónDon Rafael
• Carlos Muñoz ArosaRafael
• Guillermo MarínEyewitness
• Casimiro HurtadoPascual el Mirada
• Emilio FábregasPolice Commissioner
• Eugenio TestaJulián Azores
• Marta GrauDoña Lola
• José GoulaPostmaster