I think ESB is getting at the issue of BBC saying Norwegian in headline so if you didn't look any deeper you wouldn't know he was a Somali who has been given Norwegian citizenship, (NB Sky does same).. The Guardian says 'suspect & victims nationalities known and in the text they say
The suspect
A 19-year-old Norwegian-Somali man was arrested at the scene after being Tasered by a police officer.
Actually I don't know the guy was born in Somalia, I'm assuming that as the most likely case.
Norwegian Somali (so Somali then!!) teen stabs Russian woman to death and slashes an Israeli woman in London. If we didn't have foreigners here we wouldn't have any of this shit.