Although I sympathize with Mr. Starliper, he lost me here. I would like to see his methodology, but you can't just make it up as you go along. At some point you're just counting the number of characters in the message and making a random message out of it. The fact that none of the authorities are interested is telling, too.
I think they aren't interested because the main suspect died in '92.
The fact that the authorities don’t care just means the authorities don’t care.
You’ll find the German WW2 coding systems extremely interesting. They used ciphers which changed frequently.
Modern encryption uses extremely large prime numbers to produce those unpredictable patterns.