Besides being a crusading District Attorney, Jim Garrison was also a cryptologist. No code was too difficult for him to crack.
A researcher noticed similar notations in Clay Shaw's notebook and in Lee Harvey Oswald's notebook. Clay Shaw had written P.O. 19106 in his notebook along with the name Lee Odom. Mr. Odom had talked to Shaw about possibility of putting on a bullfight in New Orleans.
In Oswald's notebook was a similar notation, but instead of P.O., there were two Cyrillic D's (Д). To Garrison, this linked the two men. It was a ridiculous notion - the P.O. Box had been opened well after Oswald made the notation - and Oswald made the notation while he was in the Soviet Union.
Sylvia Meagher wrote a letter to Garrison saying this was all nonsense. I reproduce that letter in my book, On The Trail of Delusion, Jim Garrison: The Great Accuser.
But, there was more - the 19106 notation was also code for Jack Ruby's phone number. Here is how the code worked - this is a document that Garrison filed in court in response to a Shaw motion to have his property returned (Garrison's men had carted off a lot of stuff when Shaw was arrested).
There were many other codes that Garrison broke. Richard Billings of Life Magazine kept a diary of his time working with Garrison. Here is another code:
Garrison now has more of his code deciphering for us. He refers to a number in Oswald's notebook, on page 35 of the notebook, which appears on page 50 of Volume 16 of the Warren exhibits. He says you find there the number 6.3.91-92, and if you apply the letter arrangement ADBC, you then get 6139. He says then Oswald subtracted 4900 from that, 4900 being the block on Magazine Street which Oswald lived, and you get the number 1239, which Garrison says is the last four digits of Clay Shaw's phone number, Clay Shaw's number being 522-1239. Asked how 522 might have been part of that code, Garrison says the first letter after the dash is 9, and if you add 5, 2 and 2 -- it equals 9. He has no explanation for the 2 that follows the 9 that follows the dash.
One of the journalists covering the case decided to have a bit of fun and create their own code - the link from Garrison to Shaw.
