According to James Bryan, actor Gerry Klein, who plays the guy killed in the wheelchair, was once at a screening of the movie and couldn't quit laughing during his scenes. This annoyed a woman sitting in front of him. She turned and said to him 'that's not funny, what if that was YOU in that wheelchair?' , which only made Klein laugh more.
Mary Gail Artz (who plays Ingrid) later became a major Hollywood casting director and cast such films as Il signore della morte (1981), Nightmare Before Christmas (1993), Serendipity - Quando l'amore è magia (2001), La maschera di cera (2005), Kiss Kiss Bang Bang (2005), and many others. She never starred in any other film, besides this one.
The roles of the many nameless victims of the maniac were played by various crew members or friends of the filmmakers. These murder scenes were shot on weekends prior to principal photography.
The pink shirt Peter wears in the climax was a promotional shirt for the movie Boogievision (1977), an earlier movie from James Bryan.
Tom Drury, the actor who plays the Maniac, also worked as a singer. One of his songs can be heard playing in the deputies car early in the film.