going, oh, my god. what he's holding in his hand is an intented writing copy of the diagram we received in the mail. >> this is the sheet of paper detective ruiz found. you can see the inden tensions of the bolt threads about a third of the way down. here's the same sheet of paper enhanced by the atf crime lab. here's the original bomb diagram mailed to investigators in august. >> this is the smoking gun. >> unbelievable. couldn't believe it. exciting doesn't begin to describe. elated, maybe? >> then what happened? >> i went out and arrested paul moore. coming up, pete moore seems to be in the clear, but he's got yet another shock in store. >> there's no scale for this. this changes you forever. >> when "dateline" continues. george woke up in pain.