The letter writer mentions a TV show. It is not clear in the cipher which show he is referring to, but the Chronicle reported that the cipher was sent to the newspaper on Nov. 8, 1969, a few weeks ...

Sam Blake, an Australian mathematician, first learned of the Zodiac Killer’s unsolved ciphers — a series of encrypted messages — from a documentary in the 1990s. His interest marginally increased in ...

The envelope arrived at the San Francisco Chronicle in November 1969 without a return address, its directive to the recipient, in handwriting distinctively slanted and words unevenly spaced, to ...

James is a published author with multiple pop-history and science books to his name. He specializes in history, space, strange science, and anything out of the ordinary.View full profile James is a ...