Interviewing Anders Behring Breivik was like meeting the fictional serial killer Hannibal Lecter, a psychologist said at his trial.
Eirik Johannesen, who spent 26 hours speaking with the 33-year-old in prison, said his encounter "was almost like meeting Hannibal".
Mr Johannesen was called by Breivik's defence to back its case that he was not insane.
The 18 psychiatrists testifying at the trial of the mass killer are far from an agreement over his sanity. Teams have reached opposite conclusions about his mental state, a central issue at his trial.
Breivik admits shooting 69 people and killing eight in a bomb attack last year but denies criminal responsibility.
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