 In a 2005 interview, director Alex de la Iglesia said that the name  of the movie "Crimen Perfecto" ("Perfect Crime") is an homage to  _Dial M for Murder (1954)_ (qv), which in Spain its known as  "Crimen Perfecto" ("Perfect Crime"). Also, when Rafael bought the  movies to plan the crime, "Dial M for murder" is one of them