From their website:
On June 30, 1999, sheriff’s officers in St. Louis, Missouri discovered the body of 41-year-old Ricky McCormick. He had been murdered and dumped in a field. The only clues regarding the homicide were two encrypted notes found in the victim’s pants pockets.
Despite extensive work by our Cryptanalysis and Racketeering Records Unit (CRRU), as well as help from the American Cryptogram Association, the meanings of those two coded notes remain a mystery to this day, and Ricky McCormick’s murderer has yet to face justice.
“We are really good at what we do,” said CRRU chief Dan Olson, “but we could use some help with this one.”
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In fact, Ricky McCormick’s encrypted notes are one of CRRU’s top unsolved cases. “Breaking the code,” said Olson, “could reveal the victim’s whereabouts before his death and could lead to the solution of a homicide. Not every cipher we get arrives at our door under those circumstances.”
The more than 30 lines of coded material use a maddening variety of letters, numbers, dashes, and parentheses. McCormick was a high school dropout, but he was able to read and write and was said to be “street smart.” According to members of his family, McCormick had used such encrypted notes since he was a boy, but apparently no one in his family knows how to decipher the codes, and it’s unknown whether anyone besides McCormick could translate his secret language. Investigators believe the notes in McCormick’s pockets were written up to three days before his death.
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Over the years, a number of CRRU’s examiners—who are experts at breaking codes—have puzzled over the McCormick notes and applied a variety of analytical techniques to tease out an answer. “Standard routes of cryptanalysis seem to have hit brick walls,” Olson noted. Our cryptanalysts have several plausible theories about the notes, but so far, there has been no solution.
To move the case forward, examiners need another sample of McCormick’s coded system—or a similar one—that might offer context to the mystery notes or allow valuable comparisons to be made. Or, short of new evidence, Olson said, “Maybe someone with a fresh set of eyes might come up with a brilliant new idea.”
If you have cracked the code or want further info, go to the FBI's Website.