Help Solve an Open Murder Case

From the FBI press release:

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.”

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.”

More details and contact info at the link. And they offer these tips:

Breaking any code involves four basic steps:

1. determining the language used;
2. determining the system used;
3. reconstructing the key; and
4. reconstructing the plaintext.

Consider this cipher: Nffu nf bu uif qbsl bu oppo.

Now apply the four steps:

1. Determining the language allows you to compare the cipher text to the suspected language. Our cryptanalysts usually start with English.

2. Determining the system: Is this cipher using rearranged words, replaced words, or perhaps letter substitution? In this case, it’s letter substitution.

3. Reconstructing the key: This step answers the question of how the code maker changed the letters. In our example, every character shifted one letter to the right in the alphabet.

4. Reconstructing the plaintext: By applying the key from the previous step, you now have a solution: Meet me at the park at noon.