In the late 1960s, Northern California had it all: sunshine, Haight-Ashbury and the Grateful Dead.

Unfortunately, it also had the Zodiac Killer.

A serial killer who was never identified, Zodiac is thought to have killed at least five people — and, in letters signed with a distinctive target symbol, claimed to have killed 37.

Now, in a new book, a man living in Louisiana says that his biological father committed some of these crimes. From HarperCollins:

Soon after his birthmother contacted him for the first time at the age of thirty-nine, adoptee Gary L. Stewart decided to search for his biological father. His quest would lead him to a horrifying truth and force him to reconsider everything he thought he knew about himself and his world.
Written with award-winning author and journalist Susan Mustafa, The Most Dangerous Animal of All tells the story of Stewart’s decade-long hunt. While combing through government records and news reports and tracking down relatives and friends, Stewart turns up a host of clues — including forensic evidence — that conclusively identify his father as the Zodiac Killer, one of the most notorious and elusive serial murderers in history.

The publisher went to great lengths — or, at least, tried to look like it went to great lengths — to keep the book’s contents confidential. According to New York magazine, even the cover art was squashed. But CNN put a name to Zodiac:

Now Gary L. Stewart, a vice president at the cleaning company Delta Tech Service in Baton Rouge, is recounting his decade-long search for his biological father and has concluded that man — Earl Van Best, Jr., who’s now dead — was the Zodiac Killer, the publisher said.

Stewart told People magazine some of what he’d discovered about Best, who died in 1984:

Adopted as an infant by a loving family, Stewart never knew the identity of his birth parents until his birth mother – Judith Gilford – reached out to him in 2002. He soon learned that she was 14 when she ran away from home with a 27-year-old rare book dealer named Earl Van Best Jr., later giving birth to his child in New Orleans in February 1963 when the two were on the run from the authorities searching for Gilford, a minor. Against the wishes of Gary’s frightened, confused teenage mom, Best abandoned their month-old son in a Baton Rouge apartment building.

Other authors have claimed to have found Zodiac before, including one whose tale inspired the 2007 film “Zodiac.” Even Theodore Kaczynski, the “Unabomber,” was thought to be Zodiac. But, according to California police, cases related to Zodiac remain open. CNN:

On Tuesday, police in northern California said they weren’t aware of the book or its claims.
“It’s an open and active case, so we don’t comment,” San Francisco police spokesman Albie Esparza told CNN. “But (it’s) certainly something our homicide investigators will take a look at.”
Added Capt. Steve Blower of the Napa County Sheriff’s Office: “We have talked to many people over the years. We’ve gotten reports over the years from people who don’t pan out. This case is still open, and we still do accept tips or leads that may have bearing on the case.”

A message left for Stewart at Delta Tech was not immediately returned.