FBI experts are seeking the help of the public to make sense of two encrypted notes found on a murder victim that have stumped detectives for years.

Ricky McCormick, 41, was found dead in a field in St Louis, Missouri, back in June 1999. Two encrypted notes found in his pockets have defied the best efforts of detectives and FBI cryptoanalysts to make sense of them ever since.

The handwritten notes, written by the victim himself up to three days prior to his demise, contain a mixture of "letters, numbers, dashes, and parentheses" that have defied traditional cryptanalysis techniques.

Members of McCormick's family report that he had used coded notes since he was a boy, without letting anyone in his family into the secret of how to decipher the messages.

The FBI is looking for other samples of notes made by MCCormick or left-field ideas on how to crack the code that could be crucial to solving a 12-year-old murder mystery. Another sample of a coded note from a similar system may also help.

"We are really good at what we do," said Cryptanalysis and Racketeering Records Unit (CRRU) chief Dan Olson, "but we could use some help with this one."

McCormick's encrypted notes are one of CRRU's top unsolved cases. "Breaking the code," explained Olson, "could reveal the victim's whereabouts before his death and could lead to the solution of a homicide."

No financial reward is on offer, just the pure intellectual challenge and the satisfaction that unravelling the code might bring a killer to justice.

"Even if we found out that he was writing a grocery list or a love letter," Olson said, "we would still want to see how the code is solved."

The notes and more information on the case, along with basic code-breaking tips, can be found in an FBI appeal for information here. ®