Worked as a music composer for The Body Shop.
His film after The Manitou (1978), "The Overlords". was planned but never started production.
Died when the helicopter in which he was a passenger hit electrical power lines and crashed. He was 30 years old.
Died at the age of 30.
Wrote the script for The Manitou (1978) in three days, along with Jon Cedar and Tim Pope.
Sued by Warner Bros., which alleged that Abby (1974) was a rip-off of The Exorcist (1973).
Sued Film Ventures Internatonal chief Edward L. Montoro for profits from Grizzly (1976).
He was a big fan of Alfred Hitchcock.
Frequently used music by Lalo Schifrin and Robert O. Ragland.
Brother-in-law of J. Patrick Kelly III.
Buried in his hometown of Louisville, Kentucky. 
Made radio and TV commercials before making his first film.
Joined the Air Force at age eighteen. While serving in the Air Force Girdler was stationed in California, where he handled audio/visual services and cut his teeth by working on documentaries and educational films. Moreover, Girdler also served as a hurricane hunter in Puerto Rico prior to embarking on a career as a filmmaker in the early 1970's.
Brother of Lynne Kelly.