A Norwegian court has found confessed mass killer Anders Behring Breivik sane in the commission of twin attacks last July that killed 77 people.

The verdict Friday means that Breivik will go to prison for 21 years, a sentence that could be extended beyond that for as long as he is considered dangerous. The prosecution had wanted an insanity verdict so that Breivik would be sent to a mental hospital.

Breivik confessed to the killings that took place during a bombing and shooting rampage on a government building in Oslo and a political youth camp. He underwent two psychiatric evaluations, with one ruling him mentally incompetent and the other ruling him sane.

Breivik's defense lawyer says his client would not appeal the prison sentence.

On July 22 of 2011, Breivik detonated a bomb near an Oslo government building, killing eight people. Then he shot and killed 69 people, mostly teenagers, at a youth camp on Utoeya Island.

Breivik has said he was acting to fight multiculturalism in Norway and what he sees as a Muslim invasion of Europe.