I did say mono-citizens, sir. This dude should be serving life sentence without parole. Heck, I would prefer solitary confinement for life for these sort of people but that probably won't happen in a European country. Apparently that's human rights violation...
First let him check his mental state. From what I have heard, this guy seems to be having mental issues. But if it is found that he is in a sound mental health, then I don't support releasing him in to the public. That said, the western governments which engage in Islamic appeasement all the time should ask themselves whether they want more Breiviks in their nations.
If I remember correctly, Breivic sued the government for putting him on solitary confinement. Ridiculous. It's not as unfair as what he did to all those kids. If people like him can't be given the death penalty (long abandoned in Europe), they should at least be made to suffer a gloom lifetime in prison. Lock them up and never let them see the light of day or interact with any human ever again.