[3][4] The film starring Robert Foxworth, Stefanie Powers, Cesare Danova, Sue Lyon and Elke Sommer.

Arthur C. Pierce wrote the screenplay and co-directed the film uncredited.

It was later re-edited into a new, shorter version entitled The Invisible Strangler and released on video in 1984.

Invisible Strangler runs 85 minutes, about ten minutes shorter than The Astral Fiend, and most of the killer's dialogue lines during the murders were edited out, while new music and some entirely new scenes were added.

Studying the paranormal allows a convicted strangler to make himself invisible to kill five women who testified against him at his trial.