I think his manifesto.
They are worried there are ‘code words’ in it that’ll set off other attacks. They’re also trying to ID his network before the release it. ANY public space venue with large crowds needs to have police snipers on the lookout - like the Secret Service does for POTUS.
My theory: Paddock was part of a cell. 3-4 individuals, each with an assigned job. Someone else was to put the vehicle with the bomb into position and he’d fire on that, setting off an explosion for the escape routes. They had a cross fire ‘kill box’ plan set up. That other person or persons got cold feet and backed out. One could be the ‘you’re all going to die’ woman we’ve read about.
Odd part: He thought he would escape. How? The room was in his name, he bought the guns. Escape how?
Assuming he could get out and then to the airport - he was a pilot. But I have my doubts that he really thought he could do it.