The Zodiac Killer is the pseudonym of an unidentified serial murderer active in the San Francisco Bay Area between December 1968 and October 1969. Investigators attribute at least five killings to him, carried out in attacks on three couples and a lone cab driver across Benicia, Vallejo, unincorporated Napa County, and San Francisco. Two of the seven people he attacked survived.
The killer adopted the name in a series of letters mailed to Bay Area newspapers, in which he claimed responsibility for the murders, supplied case details, threatened further violence, and enclosed cryptograms. He signed his correspondence with a crossed-circle symbol resembling a gunsight crosshair. In his final confirmed letter, received by the San Francisco Chronicle in 1974, he claimed a total of 37 victims.
The only person ever publicly named as a suspect by police was Arthur Leigh Allen, though no charges were ever brought and his identity remains unestablished. The case is widely described as one of the most famous unsolved murder cases in American history and continues to attract amateur investigators internationally.
Case status
In April 2004 the San Francisco Police Department marked the case inactive, then reactivated it by 2006/2007. The California Department of Justice, the Federal Bureau of Investigation, the city of Vallejo, and the Napa and Solano county sheriffs have maintained the case as open.