In the late 1960's and early 1970's, a serial killer stalked parts of Northern California. The exact body count is unknown and whether or not some murders he took credit for were actually his handiwork also remains a mystery.
Assigning himself with the moniker "Zodiac" in taunting letters and cryptic codes sent to the police departments and newspaper outlets, he was never apprehended and no truly viable suspects seem to have ever developed from the limited evidence left behind at the scenes of his crimes.
In letters written to newspapers, the Zodiac serial killer in California claimed thirty-seven victims, seven of which are considered "confirmed" by police investigators. Two of those seven survived, yet were not able to provide any substantial descriptions or clues to the identity of the Zodiac. Six of these confirmed attacks were couples, three sets of two, and the survivors were males. The seventh confirmed victim was a cab driver who apparently was in the wrong place at the wrong time and had the misfortune of crossing paths with the Zodiac while the killer traversed the city of San Francisco.
Additional murders and attempted murders are the suspected handiwork of the Zodiac, with those being another couple, and three separate incidents involving solitary women (one of whom had an infant with her at the time of her attack).
The Zodiac's most active time period was from July 1969 to December 1969, where he either attacked someone or mailed a letter or coded letter during each of the months in that time frame. Prior to that period from mid-to-late 1969, the Zodiac's confirmed or suspected activities took place in 1963, 1966, and 1968 (the first two being suspected and the 1968 incident being confirmed). In March and September 1970, two more suspected Zodiac attacks took place.
Zodiac remained communicative through March 1971, and the notes, cards, and letters received after that date have not been conclusively identified as having been sent from the Zodiac killer, with the exception of one sent in January 1974 to the San Francisco Chronicle. Several other messages have been received by various agencies and entities since that time, but those have either been outright dismissed as being the work of the Zodiac or have been deemed inconclusive with regard to authorship.
There have been a small handful of suspects advanced by investigators over the years, with none being of such solidity that any arrests have been made. In the book Zodiac by Robert Graysmith, suspect Arthur Leigh Allen seems to hold the most weight with regard to viability as a suspect, but he was ruled out when DNA comparisons were made from a Zodiac letter (even though it was not determined that the DNA sample was actually the Zodiac's).
The Zodiac serial killer in California has remained popular in myth and media, with books and movies about him being written and made on a regular basis. There are also several websites devoted to stockpiling and displaying case information, evidence, letters, codes, possible suspects, possible victims, and other information relating to the Zodiac's activities and suspected activities. Not unlike Jack the Ripper, the Zodiac killer remains a fascinating subject long after his crime spree ended, and his identity remains just as elusive.