A fire broke out at the forest location in Topanga Canyon, CA that was used for the climax of the film.
Francine York didn't get along with Ray Danton during shooting. She revealed in a magazine interview that since her character wasn't supposed to get along with Danton's character in the movie, it made the scenes in which the two argue and fight with each another that much easier to do.
Tiffany Bolling said in an interview many years later that the primal scream she lets out toward the end before stabbing a guy was real. She said her life was horrible at the time and she was so frustrated with where her career was going and having to make what she felt was low budget schlock like this movie, that when it came time to scream, she let all that pent up anger come out.
Andrew Prine came up with the idea for Clement Dunne to wear a black suit and have a white bedroom in order to suggest that Dunne saw everything in black and white.
The actress who played the first victim seen on the beach was actually a stripper.