I don't follow your reasoning. The coded message was there in case he needed it. It was a message that he could decode and explain to others WHEN NECESSARY. It would have been a disaster if the code was deciphered before he was ready ...
Exactly. If it would be a disaster to have the code discovered too early, why provide clues that there is a code?
I'm still not following you. What clues did he provide?
As far as I know, no one even imagined that there was a code in the media letters until Ivins was observed throwing away "the code books" at around 1 a.m. on the morning of November 8, 2007. I imagine it even took considerable time for them to figure out WHY Ivins threw out those materials.
That act was hardly a "clue" that Ivins knew he was providing to the FBI. His home, cars, office, safe deposit box and everything else he owned was searched on November 1 and 2. Because it is COMMON for guilty persons to destroy evidence after such searches so it won't be found in the next search, the FBI watched Ivins home and, sure enough, he threw the materials into the garbage and made sure the garbage truck had hauled it away.
But the FBI agents stopped the truck when it was out of site of Ivins' home and did their search there.
I wouldn't call that "providing clues." I'd call that "making a common mistake." You might argue - with 20/20 hindsight - that he should have burned the "code books" somewhere inside his house, mixed the ashes with granola and fed it to birds in his backyard. Yeah, but he didn't know that the FBI was watching. He looked around and didn't see them. He was acting the way guilty people act when they think they are getting away with a crime.
The problem with that is that it doesn't explain why there are so many other A's and T's highlighted. Why wouldn't ATTA just highlight the 4 letters in the right order if he was putting his name into the letter? And why do it that way in the first place? Why not just sign the letter?
Someone had to read through GEB and realize that the image on page 404 was similar to the highlighted characters in the media letter. Then they'd have to realize that the condons described in the magazine article could be the code.
I hope some FBI agent writes a book some day about how they figured that out. How many people were trying to figure out why Ivins threw away one of his favorite books? How many other possible reasons could there have been?