He was described as having “light brown hair,” although it’s hard to tell (because of the time of day and the angle) what color it was. However, he does look like a sort of standard model young white guy of no particularly identifiable ethnic group.
There’s nothing that prevents him from being a Muslim convert or even from a traditionally Muslim European group (such as Bosnian) or even Chechen, some of whom are very fair skinned.
He could, as you say, just be a young white psycho. But it is odd that they’re not releasing his name.
That they aren’t saying who he is does suggest ROP. That he turned himself in suggests GVC (garden variety crazy.) I’ll be interested to see which it is, because it does sound like it’s down to those two.