Pig's blood, not stage blood, was used for the stabbing scene, for the sake of additional realism.
The narration quotes confessions of real-life killers like Peter Kürten, known as the 'Vampire of Düsseldorf'.
In the scene where the killer smashes a window when breaking into the house, the window he breaks is not stunt glass, but real glass, something actor Erwin Leder insisted on doing. He injured his hand in the process. (The glass door that Silvia Ryder throws herself through is fake glass, although she bruised herself badly when landing.)
Due to financial constraints and the controversy surrounding the film, director Gerald Kargl never directed another film after this one.
Based on an actual case of triple-murder, the "Kniesek case". Werner Kniesek, born 1946 in Salzburg - who killed three people out of pure lust in 1980 - stands as a threatening symbol of senseless death and destruction for its own sake. "I just love it when women shiver in deadly fear because of me. It is like an addiction, which will never stop", said Kniesek in front of the judge. His psychiatrist classified him as "extremely abnormal but not mentally ill"- an explosive mixture of lust for destruction and addiction to physical violence.