Troy Donahue was a clean cut matinee idol thanks to A Summer Place (a movie that got him name-dropped in Grease's Look At Me, I'm Sandra Dee), but by the time the late 60s rolled around his style was out. Warner Bros dropped his contract and the actor began growing his hair, drinking a whole lot and hanging out with a seedy crowd. And then came Sweet Savior.
That was the original release title of The Love-Thrill Murders, directed by Robert L. Roberts, New York City pornographer (he pioneered a closed circuit TV system that could pipe adult movies into motel rooms) and written (under a psuedonym) by Willie Gilbert, who co-wrote the book for How to Succeed In Business Without Really Trying*. The film was a thinly fictionalized retelling of the Manson Family murders, with Donahue as the grizzled cult leader Moon.
The film's low budget meant it had to be shot in New York City, but they did find a real pregnant actress to play the Sharon Tate part. And their version ends with Moon free, flipping the bird to the American flag - very provocative, man.
Troy Donahue would go on to keep working in and out of the studio system, eventually inspiring the character Troy McClure on The Simpsons. Sweet Savior would be rereleased under the title The Love-Thrill Murders, and would be one of the seminal influences on a wave of true crime/Manson-inspired movies that would flood grindhouses in the 70s.
* Gilbert went to school with Jerome Lawrence, Jerry Siegel and Joe Shuster. They all worked on the high school humor paper together.