The Norway man who went on a rampage killing 77 people in July was declared "insane" and could be admitted to a psychiatric institution rather than face jail time.
Prosecutor Sven Holden said the report asserts that Anders Breivik is "insane" and "delusional"
"The conclusion is ... is that he is insane...He lives in his own delusional universe and his thoughts and acts are governed by this universe,” said Holden in a press conference.
Two forensic psychiatrists, Synne Serheim and Torgeir Husby, presented their report in an Oslo district court on Tuesday.
"We have no doubt when it comes to our conclusions," said Husby to reporters.
The psychiatrists spent 36 hours total talking to Breivik. They also watched tapes of him being interrogated by police.
"It was a lot of work, demanding," Husby told reporters. "He has cooperated well."
The 243-page evaluation of Breivik will be looked over by the Norwegian Board of Forensic Medicine. The board could ask for additional information from the psychiatrists.
In July, the board told the Associated Press that Breivik would probably not be found insane because the massacre was so meticulously planned.
The ruling now means Breivik could avoid jail time. In Norway, for a defendant to be declared insane, they must have been in a psychotic state when they committed the crime. A psychotic state means the person could no longer control their behavior and has lost touch with reality.
The court in Norway can still make its own decision but usually follows expert recommendation.
Breivik admitted setting off a car bomb outside a government building that killed eight people. He then went on a shooting massacre on the island of Utoya.
Sixty-nine people were killed in the shooting. Most of the victims were teenagers.
He said was on a "crusade" against Islam in a manifesto posted on the Internet just before the rampage.