Quantico, Virginia (CNN) -- If you like spy thrillers, Sudoku and the daily crossword puzzle, you might want to try this: help the FBI crack a secret code.
It could solve a suspected murder.
Ricky McCormick's decomposing body was found in a field near St. Louis, Missouri, in 1999. It wasn't clear how the 41-year old unemployed McCormick had died, but law enforcement believed he was murdered. Their best clue: two pages of encrypted notes written by McCormick and found in his pocket.
They might tell investigators where McCormick had been, what he had been doing and who might have wanted him dead. But they couldn't break the code.
In 2001, local law enforcement turned to the FBI Cryptanalysis and Racketeering Records Unit for help. Its analysts, statisticians and mathematicians have puzzled over the two pages of numbers and letters intermittently for 10 years trying to figure out what they mean, but they haven't found the key.
"We're beat," says the head of the unit, Dan Olson.
On March 29, the FBI asked the public for ideas. In just a week and half more than 2,300 tips have flooded in. They are still being processed, but so far none of the theories or leads has solved the mystery.
Could the notes be gibberish?
Olson says they definitely are not. "We have patterns. We have very consistent character repeating sequences. There are almost rules to whatever language this is. This is not random. This is not just letters put down."
McCormick had dabbled with ciphers since he was a child and although he wasn't well educated, Olson says, his code is unlike anything he has ever seen -- unique and idiosyncratic. He hopes a member of the public might connect it with a hobby, a game or a line of work.
The FBI unit often cracks codes in just a couple of hours. It has deciphered secret communications about murder, drug transactions, illegal gambling and human trafficking.
One of the toughest cases involved a note composed by Brian Patrick Regan, a former Air Force master sergeant convicted of attempted espionage in 2003.
The note identified seven locations in a Maryland's Patapsco Valley State Park where Regan allegedly dropped documents stolen from the National Reconnaissance Office. The office builds and operates satellites for government agencies like the Central Intelligence Agency.
While in prison, Regan worked with the FBI to decipher the complex code, which he had created but, ironically, had forgotten. Eventually, they were able to associate a sequence of code with the letter "F." The key that unlocked it was the name Frank, handwritten under a gag photograph of a masked classmate in Regan's middle school yearbook.
Olson says computers aren't much use in his line of work. "These are codes that are made by humans and they're best broken by humans," he says.
A simple whiteboard, however, is an important tool. Olson and his team use one to dissect a segment of code, looking for patterns and logic in what appears to be a jumble of symbols. It is collaborative work where creative ideas and unusual insights are encouraged and exchanged.
Olson says a good crpytanalyst needs tenacity and high self-esteem. He or she can not be easily discouraged, Olson says, but sometimes needs to recognize that there is a time to step away.
Do they ever quit working on a code altogether?
It doesn't look that way. In the FBI office is a board holding copies of the FBI's "Top 10" uncracked coded communications. Over the years, some have been solved and removed. Right now, in the top slot, is a note from the "Zodiac Killer," who murdered five people in California's Bay Area in 1968 and 1969.
The notes found in Ricky McCormick's pocket are posted in position No. 3. Olson is hopeful that sometime soon, with the public's help, they too will come down from the board and questions about McCormick's death will finally be answered.
Meserve is CNN homeland security correspondent and Cratty is a senior producer.