This is a mysterious and unsolved case of a serial killer who operated in Northern California from the late 1960s to the early 1970s. The Zodiac Killer is believed to have killed at least five people and injured two others. The killer's identity has never been confirmed, and the case remains
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.