The mother of Norwegian mass murderer Anders Behring Breivik described how her "kind and caring" son transformed into an out-of-control obsessive who wore a face mask and talked of a war against Muslims, a psychiatrist told a court on Thursday.
Psychiatrist Torgeir Husby read out quotes from an interview he carried out with Breivik's mother - the first time her words has been heard during the trial of the man who has admitted killing 77 people in bomb and shooting attacks in July.
"I thought that he was turning completely crazy, I thought there must be something wrong with his head," read out Husby, quoting Wenche Behring, as a visibly nervous Breivik looked on at the hearing.
The court had earlier heard Breivik had behavioral problems as a child, and a psychiatrist had recommended he be removed from his family at the age of four.
He was kept under observation at home and Brevik's mother told Husby her son soon got over his early problems.
"He was a good student (before high school), had friends ... He was so kind, always thought of me and helped with everything possible. He was outstanding ... He was incredibly kind and caring," Husby read out.
Things started deteriorating when Breivik moved back in with his mother in 2006 after some business ventures failed, said Wenche Behring, who refused to appear at the hearing.
"We had had so much fun together then it became just politics ... He would speak of an impending civil war. He spoke loudly and intensely even as I tried to avoid those topics," she said according to the psychiatrist's account.
Husby said the mother told him Breivik started going to the gym, playing computer games in his room and became paranoid about cleanliness.
The transcript did not include any explanation on what had caused the transformation.
"He accused me of being in contact with too many people who could infect us. He ate food in his room then put the dishes by the door. He walked with his hands over his face and for a while he used a face mask."
"One time he kissed me on the cheek but it was so violent and it bothered me," she added, Husby said.
Breivik smiled frequently during Thursday's court proceedings and often turned his head, a change from his usual calm and composed demeanor.
Breivik, who first detonated a car bomb outside government headquarters killing eight, then gunned down 69 people at the ruling Labor Party's summer camp on Utoeya Island, said the massacre was necessary to stop a looming civil war as Muslims take over Norway.
He said he targeted the Labor party because it supported immigration and the children, most of whom he shot in the head from close range, were political activists.
About 10 percent of Norway's 5 million people are immigrants with Muslim communities making up around 2 percent of the total, Statistics Norway said.
The court is considering whether Breivik is sane and should be sent to prison or insane and sent to a mental institution.
Husby and another psychologist Synne Soerheim concluded he was psychotic while a second group of experts came to an opposing conclusion, leaving the five judges to decide.