The Mystery of the Zodiac Killer

The Zodiac originated the name himself in a series of taunting letters and cards that he mailed to regional newspapers, threatening killing sprees and bombings if they were not printed. Some of the letters included cryptograms, or ciphers, in which the killer claimed that he was collecting his victims as slaves for the afterlife. Of the four ciphers he produced, two remain unsolved, and one was cracked only in 2020. While many theories regarding the identity of the killer have been suggested, the only suspect authorities ever publicly named was Arthur Leigh Allen, a former elementary school teacher and convicted sex offender who died in 1992.