The Zodiac Killer was a serial killer who operated in Northern California in the late 1960s and early 1970s. The killer’s identity is still unknown. Four men and three women between the ages of 16 and 29 were targeted. The killer originated the name “Zodiac” in a series of taunting letters sent to the local Bay Area press. These letters included four cryptograms (or ciphers). Of the four cryptograms sent, only one has been definitively solved.
The Zodiac Killer is one of the great unsolved serial killer mysteries of all time, taking only second place to Jack the Ripper.
Even though police investigated over 2,500 potential suspects, the case was never officially solved. There were a few suspects that stood out, but the forensic technology of the times was not advanced enough to nail any one of them conclusively.