(Yahoo!News) – After 40 years of silence, a former California Highway Patrol officer says he knows the identity of the Zodiac killer.

In his book, “The Zodiac Killer Cover-up,” Lyndon Lafferty, 79, says the serial killer is a 91-year-old recovering alcoholic who is living in Fairfield, Calif., outside of Napa Valley. He chooses not to ID the man.

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