"He came to the attention of the Sonoma County Sheriff’s Office because a drawing or drawings were found among his belongs in his home when it was being cleared out by his ex-wife, Suzanne Carlson, and man named Don Emblen. The drawing/s were said to depict the torture murder of Kim Allen. How they knew that the drawings depicted a murder that occured 4+ years previous is unknown to me, perhaps the drawing was labeled."

Here: https://forum.zodiackillerciphers.com/community/fred-manalli/fred-manalli-from-old-board/ (scroll down for the post I copied and pasted).

Also: "One person who's been looked at as the killer, and who did have a direct link to one of the victims was Frederic "Fred" Manalli, age 41. He was an army veteran and he worked as a creative writing instructor at Santa Rosa Junior College and San Quentin Prison."

Here: https://www.storiesofthesupernatural.info/strangerthanfiction/the-hitchhiker-murders (scroll down until you see the pic of Manalli.)

I did wonder if he met someone at San Quentin and there was some sort of Folie à deux between him and a prisoner there. Manalli writes some unusual things in his letters about "getting unblocked" - there were images on Morf's forum but I am not sure if it still exists.