Crooks remained prone during the entire firing sequence and there is a pretty good cell phone video of the whole thing. There are probably several videos. He was in plain sight of a crowd for at least a minute.
He fired eight shots. The first three shots sound completely different from the next five shots. You do not need sensitive audio analyzers to tell the difference. You can plainly hear the difference when listening to the track from the podium microphone.
Does that mean there was another shooter? Maybe.
More likely (IMO) he was using a magazine mistakenly loaded with two different ammunition types and was doing rapid fire because he could not tell if he actually hit Donald Trump in the first three shots.
He paused to check his results - and one of the counter-snipers got him.
The pictures of dead Crooks on the roof were taken after quite a bit of alterations to the scene. He was obviously turned over to the side, perhaps to search the body. The rifle was moved a good fifteen feet away. It is impossible to tell if the backpack was moved or if Crooks abandoned it along the way.
Videos taken as he was crawling up the roof do not show he was carrying a backpack. The story that he turned and pointed his rifle at a police officer is not supported by the video sequence.
he has a bullet would where entry is lower than exist on his leg...and blood is at the exit wound. seen in Grassley video
this would appear he was shot from behind and a lower point but I dont know squat about forensics
I do remain troubled by the first shot because we have video evidence of Crook showing there was no recoil when the first shot happened.
There is still more digging to be done here imho.