Police suspect that a ransom note offering the return of a stolen Enigma machine may contain coded clues as the whereabouts of the historical artefact.
Enigma was used by the Germans in the second World War to encrypt secret messages.
Police say that although the note is written in plain English its curious style and appearance of an undisclosed code word leads them to suspect a secret code, buried within the text. Experts code breakers have been called in to unravel the message
The author of the note claims to be someone operating on behalf of the new owner of the Enigma machine. That owner, the note says, purchased the machine without realising it was stolen.
It asks for £10,000 compensation and immunity from prosecution in return for the machine.
The machine was taken from the Second World War museum Bletchley Park in Buckinghamshire. Bletchley was the wartime headquarters of allied code breakers who deciphered Nazi's messages encoded with Enigma machines. British mathematician Alan Turing, who is regarded as one of the fathers of modern computing, led code-cracking efforts at Bletchley.
Museum curators at Bletchley are desperate to see the machine returned. "We are very hopeful and are following all avenues," says a spokeswoman.
Enigma machines were used during the Second World War to create the Enigma code -- messages used by the German army. Bletchley Park was at this time the location of Station X, the code-breaking unit which succeeded in cracking Enigma code.
The stolen machine one of only three remaining machines in the world that were used by the German high command and is valued at around £100,000. Its theft sparked an extensive police investigation and caused the Bletchley museum to introduce new security measures.