The trial of confessed Norwegian mass killer Anders Behring Breivik entered its last day Friday with the defense seeking to prove he was sane when he launched twin attacks last July that killed 77 people.

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

Breivik has told the court that the report declaring him insane was based on “fabrications” by court-appointed psychiatrists. He has previously said an insanity ruling would be “worse than death.”

If judged to be insane, Breivik would likely be committed to a mental institution instead of a prison. If deemed mentally competent, he faces a 21-year prison sentence which could be extended beyond that for as long as he is considered dangerous. A ruling is expected in July or August.

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