If this is the guy (not saying he isn’t). I suspect that there were signs before hand.
How was his personal life? Did anyone in his circle of friends notice anything? People don’t just snap, it is a process.
This was planned and executed by someone who put a lot of thought into it. Not by a guy who had a bad day and went over the hill. There where signs.
Getting some info from a neighbour.
He seemed to be a narcisist.
I.e, Believing he was a genious not properly acknowledged. Acted very pedantic and anal. Apparently even his World of Warcraft friends considered him a bit of a nerd. Seems like a very insecure man.
At the same time I am wondering if his online posts were a scam. He attacks the EDL for being too aggressive...