Exchanges between psychiatrist Gilles Chamberland and defence attorney Luc Leclair capped the sixth and final day of the Crown expert's testimony on Wednesday.
The issue of Magnotta's mental state is key as he has admitted to causing Jun Lin's slaying in May 2012, but has argued he should be found not guilty by way of a mental disorder.
Defence psychiatrists have testified they believe Magnotta, 32, was psychotic, had been untreated for schizophrenia for at least two years and was unable to tell right from wrong when he killed and dismembered the Chinese engineering student.
Chamberland doesn't believe Magnotta is schizophrenic and he said nothing suggests the accused didn't know that killing the 33-year-old Lin was wrong.
The Crown doctor believes Magnotta's schizophrenia diagnosis from 2002 was made in error and that he more likely suffers from a variety of personality disorders that better explain his behaviour.
Leclair asked Chamberland if there was any logic to his conclusion as he grilled the Crown witness about a thick pile of medical documents that contain repeated mentions of Magnotta being schizophrenic.
He said there was no evidence of drug abuse, which Chamberland has suggested was a likely trigger for Magnotta's previous documented psychotic episodes.
Leclair questioned the witness about why he didn't talk directly to any of the psychiatrists in those files. One of them saw Magnotta for several years.
Chamberland said he was hired to give an opinion on expert testimony. He weighed the views of those expert reports and various medical files against the opinion of the last psychiatrist Magnotta saw, Dr. Joel Paris, in April 2012.
Chamberland leaned more to Paris, a Montreal doctor who testified that he found no signs of schizophrenia in Magnotta based on an hour-long evaluation about one month before Lin's slaying. Paris diagnosed him with a personality disorder.
"For me, one hypothesis had more weight than the other," Chamberland said.
That conclusion in his report is similar to the one Chamberland had when he gave media interviews in 2012 about the Magnotta case before he was hired as a Crown expert.
During those interviews, he'd already cast doubt on Magnotta's mental illness. In one radio interview played to the jury Wednesday, Chamberland refers to the accused as a "psychopath" and "sadistic" based on public information at the time.
He said he didn't think Magnotta was ill and that the accused knew exactly what he was doing.
Leclair suggested Chamberland had long made his decision about the case.
Chamberland denied that, saying he made a finding based on the testimony and evidence heard by the jury.
"It confirmed the opinion I had," he said of what he took from the evidence.
The jury also heard Chamberland was solicited by the defence to evaluate the accused in July 2012. He said he would have been open to doing so but that he had already committed just days earlier to working with the Crown.
The accused declined to meet with Chamberland. In an agreed statement of facts, Magnotta's lawyer made his intentions clear in April 2014.
"I hereby advise you that Mr. Magnotta has declined your invitation to meet with any Crown attorney-retained psychiatrists in the above noted matter," Leclair wrote to prosecutor Louis Bouthillier.
The trial continues Thursday.
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