The Zodiac Killer was a serial killer who operated in Northern California for ten months in the late 1960s. His identity remains unknown.

The Zodiac coined his name in a series of taunting letters he sent to the press until 1974. His letters included four cryptograms (or ciphers), three of which have yet to be solved.

The Zodiac murdered five known victims in Benicia, Vallejo, Lake Berryessa, and San Francisco between December 1968 and October 1969. Four men and three women between the ages of 16 and 29 were targeted. Others have also been suspected to be Zodiac victims, but there has been thus far no conclusive evidence to link them to the killer.

In April 2004, the San Francisco Police Department marked the case "inactive", but reopened it some time before March 2007. The case remains open in other jurisdictions as well.

---http://en.wikipedia.org/wiki/Zodiac_Killer