A re-edited version released in the U.S. was called "Penetration", and featured hardcore porno footage with adult-film stars Harry Reems and Tina Russell. It was advertised as a porno featuring actor Farley Granger, who was in the original film but had nothing to do with the re-edited version. Granger threatened the distributors with a major lawsuit for the unauthorized use of his name in the new version, and they subsequently withdrew the film from US distribution, but not from Europe.
Title is a paraphrasing of Alberto de Mendoza's line from Sergio Martino's A Cauda do Escorpião (1971) of the previous year: "In my opinion, the murderer's a sex maniac."
Italian censorship visa # 60778 delivered on 2 August 1972.