Fernando Di Leo admitted that, with a critical eye, the scenes at the Police Station among the "fascist" Commissario and the "communist" Mercuri should be taken off because they take strength out of the main story. But the work of actors Frank Wolff and Luigi Pistilli was so good that he couldn't absolutely cut it off.
First part of Fernando Di Leo's "Milieu Trilogy" also including La mala ordina (1972) and Secuestro de una mujer (1973).
Many of the minor characters, like Rocco's thugs, were played by non-professional locals that Fernando Di Leo thought looked interesting.
Actor Frank Wolff died by suicide shortly after completing his scenes, so his English dubbing had to be completed by his frequent co-star and former roommate Michael Forest.
In 2006, a clip from this movie (Moschin comes back to the disco where Barbara Bouchet is dancing) has been used by group Vinylistic as video-clip for their song "Record Player".