The Zodiac Killer was a serial killer active in California in the late 1960s and early 1970s. He was never formally identified or charged, though a number of people have since written books and articles claiming to have named him.
There are four main Zodiac Killer Ciphers / cryptograms that are widely believed to have been sent by him:
* Z408 – 31 Jul 1969 – (solved)
* Z340 – 08 Nov 1969 – cipher (unsolved)
* Z13 – 20 Apr 1970 – “my name is” cipher (unsolved)
* Z32 – 26 Jun 1970 – the “map code” cipher (unsolved)
There are also several other ciphers which have been attributed to him (but which seem rather more likely to be hoaxes and/or copycats), most notably:-