Alright anons, after a fucking shitload of research I believe I have found the shooter. Check posts by 00278b:

https://archive.fo/FF6XP

This is very out of place. First and foremost 8chan never discusses accelationism so that alone is out of place BUT on top of spouting ideas on things in this, this poster also looks to be gathering intel because that intel ends up in the manifesto from those comments. On top of that, just read those posts and tell me that isn't him. That is fucking him.