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. 
 
 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. ||||| Lyndon Lafferty and his cohorts are like a lot of unofficial sleuths trying to solve the 42-year-old Zodiac serial killer case - utterly convinced they've cracked it, obsessive about their research, and dismissive of any theory that doesn't match theirs. 
 
 But there's one thing Lafferty's ad-hoc gumshoes have that most of the others don't. 
 
 They have badges. Retirees' badges - but badges nonetheless. 
 
 Across the nation, at least a dozen law enforcement officials - both active and retired -have taken it upon themselves to try to solve the mystery of the killer who fatally shot or stabbed five people in the Bay Area in 1968 and 1969 and sent almost two dozen taunting letters stuffed with cryptograms to individuals and newspapers, including The Chronicle, until 1974. 
 
 They pore over the ciphers and come up with translations they say lead to everyone from an already convicted serial slayer from Kentucky to a Southern California officer's father. 
 
 Official investigators in Napa County, Vallejo and San Francisco - the Zodiac's killing zones - usually have a few choice words for the amateur tipsters who contact them each at a clip of at least a half-dozen a week. Among the more common labels: kooks, publicity-hunters and liars. 
 
 Law enforcement tips 
 
 But when it's a cop giving the clues - well, that's something different. 
 
 Lafferty and another of his sleuthing crew, for instance, used to be California Highway Patrol officers. Another member of the team was a police detective, and yet another was a naval intelligence officer. 
 
 "There are so many crackpots and theories, but we take the ones that come in from ex- or current law enforcement a little more seriously," said Pat McMahon, a detective with the sheriff's office in Napa County, where the Zodiac stabbed two people, one fatally, in 1969. 
 
 He said it's not surprising that others in law enforcement would take an interest in the Zodiac. After Jack the Ripper, it's probably the most infamous unsolved murder case in history - and police are drawn to unsolved mysteries like cats to catnip, McMahon said. 
 
 "We're just that kind of people," he said. "We're nosy, and we want to know the unknowable." 
 
 Wide gamut 
 
 Among those nosy people is Chicago police Lt. John Lewison, who contacted the FBI in the spring to say he'd cracked enough of the Zodiac's cryptic messages to discern the killer's initials. He's not revealing them publicly. 
 
 There are also former Colma Police Chief Raymond Ottoboni, who contends that the Zodiac killed at Lake Tahoe, former Los Angeles police Detective Steve Hodel, who fingers his own father as the Zodiac, and Dr. John Averitt, a police psychologist in Cookeville, Tenn., who just released an online documentary re-exploring old theories of the Zodiac's involvement in a pair of killings in Santa Barbara. 
 
 Some send thick packets to media outlets and investigators, such as retired police Detective John Cameron of Great Falls, Mont., who says the Zodiac is convicted quintuple-murderer Edward Edwards of Kentucky. 
 
 "His handwriting matches up, the clues match up, and I believe he killed about 118 people," Cameron said. Edwards died in April in Ohio, three months before he was to be executed. 
 
 No smoking gun 
 
 Napa detective McMahon said his department has looked into several of these theories, including Cameron's, "but my problem is the smoking gun is not there yet on any of these." 
 
 Lafferty's crew is apparently the biggest yet. 
 
 The 78-year-old retired CHP officer and two of his fellow sleuths - ex-Vallejo police Detective James Dean and former Navy intelligence officer Jerry Johnson - worked on the Zodiac case while on active duty. The rest of his team includes another ex-CHP officer, a minister and a local historian. 
 
 "Look, I know what most people think of Zodiac theories, and there have been so many over the years that if a person walked into the Vallejo Police Department right now and said he was the Zodiac, they'd tell him to get out," Lafferty said. "But I do feel that we have a very credible case." 
 
 He said the Zodiac is an elderly alcoholic living in Fairfield who was motivated to kill by jealousy over his wife's affair with a prominent local man. 
 
 Man driven by rage 
 
 Lafferty dragged himself into the Zodiac zeitgeist in August 1970, nine months after the last confirmed killing, when he became suspicious of a man parking at Vallejo highway rest stops.
– The Zodiac killer who terrorized the San Francisco Bay Area is still living in northern California, says a new book by a former state police officer. The Zodiac is blamed for at least five slayings beginning in 1968. No one was arrested for the murders, and police stopped hunting for the killer 2004. Former Highway Patrol Officer Lyndon Lafferty is convinced the Zodiac is a 91-year-old alcoholic living in Solano County, who Lafferty refers to using a pseudonym because of safety concerns. His case is strong, indicates the San Francisco Chronicle, which received two dozen taunting letters from the Zodiac during his bloody spree. Lafferty told the Chronicle in an earlier interview that he discovered the suspect's name spelled out in the cyphers that marked the Zodiac's letters to the newspapers. Lafferty helped investigate the case on the job after the murders, and says in his book, The Zodiac Killer Cover Up, that he developed solid leads linked to his suspect. The information was squelched by officials, however, including by a judge having an affair with the suspect's wife, says the former cop. Lafferty wrote the book with help from six other investigators, some of whom worked the case while it was unfolding. “As God is my witness, my partners and I 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 will only say that the case remains unsolved.