According to Ulli Lommel, he got along very well with Donald Pleasence, saying he was "an angel" to work with.
The Shooting Ranch Film Studio in Gleason, Wisconsin, where this film and The Demons of Ludlow (1983) were filmed, was demolished in 1988.
The priest that is in the film was in two other Bill Rebane films. He was Sheriff Cooper in The Capture of Bigfoot (1979) and played George in The Game (1984) under a different name: "Stuart Osborn".