This is a true crime story about the mysterious serial killer known as the Zodiac Killer. The Zodiac Killer terrorized the San Francisco Bay Area in the late 1960s and early 1970s, leaving behind a series of cryptic messages and unsolved murders. The case remains unsolved to this day
From Wikipedia
The Zodiac Killer is an unidentified serial killer who murdered at least five people in the San Francisco Bay Area between December 1968 and October 1969. The Zodiac attacked three couples and a cab driver in Benicia, Vallejo, unincorporated Napa County, and the city of San Francisco. Two of the Zodiac's seven victims survived.