All the press reports I have seen today have described this individual as a right wing Christian fundamentalist.
When this story first broke yesterday, the press I saw hinted, but did not categorically state, that this was this was a suspected attack by Islamic extremists. The wider public, I have no doubt, assumed this was the work of Islamic terrorists. Unfortunately, this is the assumption in the psyche of this nation, post 9/11 7/7, bomb plots etc. This situation is no different to the 70s, 80s and early 90s, when any explosion/paramilitary style killing was immediately pinned on the IRA.
The difference with a Christian fundamentalist/right wing group/individual doing this is that the public is not reacting by beating up anyone who looks like a Christian or verbally abusing people who are Christian or firebombing Christian places of worship
That's because the "public" minded to do this sort of thing would have to go look in a mirror and beat themselves up. There is not enough "them and us" about this story to allow the self appointed kangaroo court to go out and beat up a few "darkies" or whatever in 'revenge". In the 70s/80s, people with Irish accents were commonly targeted for attack whenever there was an IRA killing.
Some random nut in a country few of us really have any affiliation with is not going to stay news for long. Amy Winehouse has already eclipsed this in tomorrow's headlines. The Sun, being unable to froth rabidly about Islamofascists, is headlining the Norwegian killing with a football angle. Yes, a football angle, Norway has cancelled all football as a mark of respect. This is how the hoi polloi are being fed this news.
As with Timothy McVeigh, a patriot who went to war, then turned against his country, the real concern behind this tragedy should what has driven this man to turn against his countrymen, not whatever trite labels - Christian, Nazi or whatever - should or should not be pinned on him.