Several days after the arrival of the three letters, mailed to the San Francisco Chronicle, San Francisco Examiner and Vallejo Times-Herald, the 408 cipher was cracked on August 8th 1969 by schoolteacher Donald Gene Harden and Bettye June Harden (née Tischer) of Salinas, California. The Vallejo Police Department received a call at 6:35 pm on 8/8/69 from George Murphy at the San Francisco Chronicle, who informed them that Donald Harden of 54 Chestnut Street had broken the code and sent his worksheets (including the cipher key) to the Chronicle The worksheets were retrieved by police from the Chronicle later that day.
Donald Harden and his wife used homophonic substitution to identify the solution, after spending just over 20 hours on the cipher. Vallejo Detective Sergeant John Lynch was left partially disappointed that the decoded cipher turned out to be the killer's thoughts and ramblings, containing numerous spelling errors (either by design or otherwise), yet it failed to reveal his identity as the killer had promised.
Some people believe the 18 unsolved characters at the foot of the cipher could harbor a second code, that may yet reveal a hidden message. However, it's very likely that the Zodiac Killer inadvertently dropped a line from his original draught message when transitioning from the San Francisco Examiner to San Francisco Chronicle. He effectively omitted "lone or stray people" from his original message (shown above right). In other words, there was never an intention by the Zodiac Killer to leave 18 unexplained characters at the foot of the 408 cipher. This concept is featured in The Original 408 Cipher article.
The 408 cipher was independently solved by the FBI in Washington, who corroborated the validity of Donald Gene and Bettye June Harden's solution.
The 408 Cipher contained the phrase "the most dangerous animal," believed to be referring to the short story 'The Most Dangerous Game' by Richard Connell, first published on January 19th 1924. It chronicled a man called General Zaroff who lived on Ship-Trap Island, where he indulged himself by capturing shipwrecked sailors before equipping them with clothes, a hunting knife and food, before releasing them with a three-hour head start. At which time he would hunt them down and kill them. However, if they were fortunate enough to survive for three days he would grant them their freedom.
General Zaroff had become bored with just hunting wild animals, stating that it posed no challenge and switched to hunting humans instead. The 408 cipher would mirror this sentiment by stating "I like killing people because it is so much fun it is more fun than killing wild game in the forest". It is thought that the Zodiac Killer may have drawn his inspiration from this short story (or subsequent movie), particularly in view of his next correspondence, the Debut of Zodiac letter on August 4th 1969, in which he revealed he shot David Faraday and Betty Lou Jensen with a pencil flashlight attached to his firearm to better sight his victims. It wouldn't go unnoticed either, that both General Zaroff and Zodiac began with the same alphabetical letter.
The Most Dangerous Game has been adapted for screenplay, most notably in the 1932 version starring Joel McCrea and Leslie Banks. Another version along similar lines was the 1945 production A Game of Death produced by Herman Schlom and Sid Rogell, directed by Robert Wise and starring John Loder and Audrey Long.
The actual cipher itself (shown below) was split into three sections of 136 characters each and mailed to three newspapers on July 31st 1969. The newspapers were the San Francisco Chronicle, San Francisco Examiner and Vallejo Times-Herald, all of which decided to publish. The codes were accompanied by details of the Lake Herman Road murders and Blue Rock Springs attack, that were specific to the killer and unknown to the public. The three letters also came with a warning "If you do not print this cipher by the afternoon of Fry.1st of Aug 69, I will go on a kill ram-Page Fry. night. I will cruse around all weekend killing lone people in the night then move on to kill again, until I end up with a dozen people over the weekend".
However, some of law enforcement were still skeptical that the letter writer and murderer were one and the same, including Vallejo Police Chief Jack E. Stiltz, who in two newspaper articles on August 2nd and 3rd asked the author of these letters to provide more details to corroborate his involvement in the murders. The Zodiac Killer duly obliged, when on August 4th 1969 the Debut of Zodiac letter arrived at the San Francisco Examiner declaring the now infamous words of "This is the Zodiac Speaking". View letter here.
GREEN: CHARACTERS USED FROM COLUMNS ABOVE.
RED: CHARACTERS NOT USED FROM COLUMNS ABOVE.
"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 - it 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 paradise and all the (lone or stray people) 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".
The possible missing wording in the 408 cipher plaintext.
This concept is featured in The Original 408 Cipher article.
Here are four articles examining an alternative to the "missing line" concept, outlined at the beginning of this page.
THE 18 UNSOLVED CHARACTERS [PT1]
THE 18 UNSOLVED CHARACTERS [PT2]
THE 18 UNSOLVED CHARACTERS [PT3]
THE 18 UNSOLVED CHARACTERS [PT4]
On August 11th 1969, a letter was received by Sergeant John Lynch of the Vallejo Police Department under the title of a concerned citizen, containing a brief typewritten message and the key for the 408 cipher. The card read:
Dear Sergeant Lynch, I hope the enclosed "key" will prove to be beneficial to you in connection with the cipher letter writer. Working puzzles criptograms and word puzzles is one of my pleasures. Please forgive the absence of my signature or name as I do not wish to have my name in the papers and it could be mentiond by a slip of the tongue.
With best wishes. concerned citizen. For a three part analysis of this correspondence, click here.