Claudio Fragasso envisioned the film as a tense psychological thriller with little to no gore. The original cut of the film resembled his vision, but the producers were not happy with the cut that Fragasso turned in, feeling that it lacked violence, so Bruno Mattei was tasked with shooting additional scenes to add more gore into the film.
Claudio Fragasso always intended for the film to be called "Night Killer". The producers renamed it for the Italian release, calling it "Non aprite quella porta 3" to make it an unofficial sequel to Tobe Hooper's The Texas Chain Saw Massacre (1974) which was released in Italy as "Non aprite quella porta" (Do Not Open That Door). Fragasso was not happy with the title change for the Italian release.
Director Claudio Fragasso was not fond of the gore scenes that Bruno Mattei shot and added into the film as it went against the kind of film he wanted to make which was less violent and more psychological.
Night Killer (1990) was released in Italy as an unofficial sequel to The Texas Chain Saw Massacre (1974), the exact same year that the official sequel Leatherface: Texas Chainsaw Massacre III (1990) was released.
According to co-writer Rossella Drudi, the film was inspired by a true story about a woman who was stalked years later by someone who might have been a prior assailant.