OSLO - A psychiatric expert who concluded Norwegian far right mass killer Anders Behring Breivik was sane begun to doubt his diagnosis after watching the defendant's lack of emotions during the early stages of the trial, he told the court on Monday."Could he have psychosis?" said psychiatrist Terje Torrissen. "I thought, how is it possible to sit through this without showing any sign of emotion?"To erase his doubt, Torrissen asked for another meeting with Breivik while his trial for the murder of 77 people, mostly teenagers at the ruling Labour Party's summer camp, was well underway.The request led to a 20-minute conversation between Breivik and the psychiatrist, not known publicly until Monday, that convinced Torrissen that his original conclusion was correct and Breivik was legally sane, he said.