The man's defense counsel, John Christian Elden, has filed to reopen cases involving 19 convictions since 1992.

District attorney Tormod Haugnes told newspaper Stavanger Aftenbladet that authorities have little choice but to acquit since it is not possible to imprison the mentally handicapped.

"New rules give him the right to commit crimes for the rest of his life, without punishment," Haugnes told the paper. "This is the most extreme result of the new penal code, where preventive detention is replaced with custody and compulsory treatment."

Elden told Aftenbladet that his client could demand compensation for the unjustified imprisonment for the seven to eight years he served for the convictions, and said the damages could likely amount to millions of crowns.