When the producers of Columbia Pictures came to Spain in 1967 to promote the film version of Truman Capote's 'In Cold Blood', they found that the Spanish title ("A sangre fría") was already recorded by a 1959 Spanish film (this one) that was titled the same. So the powerful American major pressured that, in the future, Juan Bosch's film would be commercially exploited under the title of 'Trap at dawn' ("Trampa al amanecer").