The story is inspired by the real character of Pietro De Negri, better known as Er Canaro (from Roman dialect: "the dog keeper"). De Negri lived in the Rome's suburb of Magliana. At the age of 27, he killed former boxer, quarter tough guy, and fellow cocaine addict Giancarlo Ricci. The so-called Canaro's killing is notable for being one of the most gruesome crimes carried out in Italy, particularly because the victim watched powerless during the excessive mutilation.