The movie is vaguely inspired by a true crime. Roberto Aparecido Alves Cardoso was only 16 years old in 2003, when was arrested in Brazil for the killing and torture of a teenage couple. Some elements of the screenplay were inspired by the Australian Serial Killer Ivan Millat.
At the end of the film is mentioned something that the killer would have said when he was arrested. Roberto Aparecido Alves Cardoso, the killer from the real case in which the film is inspired, actually said "I killed because I wanted to" when asked why he killed the couple of teenagers.