change of clothes in the backpack?
Not going to front like I am some firearms shooting expert, but he doesn't seem that confident or experienced. He hesitates. His first shot hit him in the calf. That's not missing by a few inches, or hitting the chest not the heart. That's someone who hasn't killed before. Doesn't go up close for the head shot either. Which shows restraint, maybe fear. Didn't go and shoot him multiple times in the head or anything. but he also could have left him alive.
Walks not runs, which is how shooters with "trigger time" in Mexico do it. So, he did his research on everything. Seems to me more like the recent presidential asssination attempts type of suspect. Online fanatics.