4. Ricky McCormick Notes
When the FBI looks for help from amateur sleuths, then you know they've got a real mystery on their hands.
After the deceased body of a 41-year-old man called Ricky McCormick was found in a cornfield, the FBI couldn't find anything to suggest how he'd died. It might have been a murder or natural causes, but even the autopsy revealed nothing.
But, they found more than just a body, as McCormick also came with crumpled notes in his pocket, filled with spontaneous letter combinations and split into speech-bubble like sections. Naturally, this arose a tonne of suspicion, but the Bureau were just as unsuccessful at cracking it as they were figuring out his cause of death.
In a fascinating response, rather than keeping this mystery secret and attempting to break the code themselves, the FBI opened it up to the public, offering anyone who felt the itch to give it a go. As of yet, nothing has been solved, but who knows, perhaps you could be the one to change that.
If you do feel up to the challenge, then take a look.