The Zodiac killer, a serial killer who claimed in letters to newspapers to have murdered dozens of people back in the 1970s, has been the subject of a number of books and films.

The latest is a book called The Zodiac Killer Cover-Up written by a former California Highway Patrol officer named Lyndon Lafferty.

According to the book’s website, the team of investigators working on the case discovered the killer back in 1971.

The Los Angeles Times has more: “Lafferty claims the killer is now a 91-year-old man living in Solano County. The book uses aliases and does not identify the alleged killer by name. Lafferty claims he and other lawmen investigated the suspect in the early 1970s but were stymied by ‘power brokers’ in Solano County.”

The killer, whose identity is still a mystery, has yet to be apprehended.