The FBI has verified that codebreakers have cracked the famed 340 ciphers employed by the Zodiac Killer more than 50 years ago. A serial murderer going by the moniker “Zodiac” murdered at least five people in California in the late 1960s and early 1970s. The assassin delivered taunting messages to the press using a cipher, in which letters changed for various letters or numbers, during his binge (or in the case of the Zodiac killer, a series of symbols).
The initial letters, each carrying a different section of the cipher, were mailed to three newspapers in the Bay Area. The ciphers (or cryptograms) printed as Zodiac threatened to murder again if his orders were not fulfilled. On August 8, 1969, Donald Gene and Bettye June Harden decrypted the cipher by hand, which was simpler than later attempts. It said:
“I LIKE KILLING PEOPLE BECAUSE IT IS SO MUCH FUN IT IS MORE FUN THAN KILLING WILD GAME IN THE FOREST BECAUSE MAN IS THE MOST DANGEROUS ANIMAL OF ALL TO KILL SOMETHING GIVES ME. THE MOST THRILLING EXPERIENCE IS EVEN BETTER THAN GETTING YOUR ROCKS OFF WITH A GIRL THE BEST PART OF IT. IS THAT WHEN I DIE I WILL BE REBORN IN PARADICE AND ALL I HAVE KILLED WILL BECOME MY SLAVES I WILL NOT GIVE YOU MY NAME BECAUSE YOU WILL TRY TO SLOW DOWN OR STOP MY COLLECTING OF SLAVES FOR MY AFTERLIFE EBEORIETEMETHHPITI”?
Based on this, it’s incredible that he could come up with a cipher complex enough to fool the FBI for years but couldn’t spare the time to double-check his spelling or ask a friend to “look, try not to read too much into the content but could you have a quick check that my grammar’s ok?” The letter included no significant clues, except the fact that the killer had some strange illusions, wanted to improve his writing, and maybe motivated by The Most Dangerous Game, a film about a person who was chased by an aristocracy for fun.
The killer’s ciphers got more sophisticated after the initial communication. One has eluded decoding for 51 years, despite containing 340 characters. A group of codebreakers agreed to attempt to crack the code since they knew it would be difficult.
Software assisted David Oranchak, Sam Blake, and Jarl Van Eycke in cracking the cipher, first by identifying the numerous different reading directions that might be utilized if the cipher was transpositional. Oranchak discovered that one method for transposing the cipher disclosed bits of messages such as “wish you are,” “trying to capture me,” and “or the gas chamber” by chance. This provided them hints that the message was not recorded in one large block as it had given, but rather in three smaller blocks of text consisting of nine lines, nine lines, and two lines.
