According to one of his biographies, one of the directors who was offered this project, but turned it down, was a then young filmmaker called George Lucas. Wikipedia states: ''George Lucas was offered the chance to direct, but he turned it down in favor of focusing on finding a studio for Locura de verano (1973)''.
Cast members, Robert Duvall and Donald Sutherland, have also both appeared in M*A*S*H (1970), The Eagle Has Landed (1976) and Los usurpadores de cuerpos (1978).
Jennifer O'Neill replaced Susan George in the leading lady role of Paula Booth. This was, according to a 1973 edition of the 'Filmfacts' publication, due to the height difference between her and leading man actor Donald Sutherland whose height at the time measured about six-foot-four-inches.
Producer Martin Elfand and screenwriter Alan Trustman were attached to produce this picture at one time according to an article published in the 15th September 1971 issue of show-business trade-paper 'Daily Variety'. The former later was a producer on another heist movie which was Tarde de perros (1975).
The movie has ''plot similarities'' with the earlier and then recent heist movie Sociedad para el crimen (1968) according to Lee Pfeiffer at 'Cinema Retro'. Alan Trustman was a screenwriter on both productions.