It’s been 40 years in the making, but ex-California Highway Patrol Officer Lyndon Lafferty’s book about the man he believes is the Zodiac killer has been released.

Lafferty’s book — “The Zodiac Killer Cover-Up, AKA The Silenced Badge” — uses a pseudonym for his suspect, but in 442 pages, he lays out quite the case. The man who fatally shot or stabbed five people in the Bay Area in 1968 and 1969, and who sent nearly two dozen cryptic, taunting letters to The Chronicle and others until 1974, is a 91-year-old alcoholic living in Solano County, Lafferty writes.

Ex-CHP Officer Lyndon Lafferty and his Zodiac sleuthing crew / Photo Brant Ward, S.F. Chronicle

Lafferty calls his suspect George Russell Tucker, and he told The Chronicle he didn’t use the man’s real name because of privacy and safety concerns. The 79-year-old ex-CHP officer maintains he encountered the man in Vallejo in 1970 and developed clues with the late Solano County sheriff’s Sgt. Leslie Lundblad, but that the case was squelched by power-brokers in the county — including a judge who was having an affair with the suspect’s wife.

Lafferty researched the book with the help of six fellow sleuths, including other law enforcement officers who investigated the Zodiac case during its height, and he calls his group “The Mandamus Seven.” A mandamus is a writ issued by a court mandating an official act.

The usual heated back-and-forth of opinions about this latest theory has erupted on Zodiac online forums — something Lafferty has already endured after airing his theory elsewhere, including in a story in The Chronicle last year.

“As God is my witness, my partners and I (the Mandamus Seven) have always tried to share our material and our case with the proper authorities, but in the past 40 years the latter have ignored and stymied and stonewalled us again and again,” Lafferty writes.

Police in San Francisco and other areas where the Zodiac hunted still say the case is unsolved.