With the jury deliberations in the Luka Magnotta murder trial continuing to a seventh day, it's not clear whether jurors are taking their time parsing the complexities of determining whether the 32-year-old was in his right mind when he killed university student Jun Lin or whether they've hit an impasse.

Experts say it’s not unusual for jurors in complex murder trials to deliberate for several days, but it could be a sign they can't reach a unanimous verdict, and a deadlocked jury would mean a mistrial.

"As time goes by, the possibility of a mistrial obviously becomes more significant, but in the meantime, I think they're just going through the process, because they haven't come back and asked a whole bunch of questions​," said Patrick Baillie, a Calgary-based lawyer and forensic psychologist who has provided expert testimony in several NCR cases.

(So far, the jury has asked the judge only one legal question and on Friday requested technical help viewing video evidence.)

We asked Baillie and two other experts to weigh in on what types of issues the sequestered jury might be grappling with.

1. Conflicting expert testimony

Since Magnotta has already admitted he killed Lin on May 25, 2012, in an agreed statement of facts, the case rests on the question of whether he was suffering from a mental disorder that rendered him incapable of appreciating the nature and quality of the act or of knowing it was wrong — which is the definition of being not criminally responsible (NCR) under Section 16 (1) of the Criminal Code.

In many NCR cases, the experts for the opposing sides don't differ significantly in their assessment of the defendant's mental state, but at the Magnotta trial, the Crown and defence psychiatrists who testified presented the jury with two very different diagnoses.

The defence experts testified that Magnotta suffers from schizophrenia and that when he killed Lin he was in a delusional state that made him believe Lin was a government agent sent to kill him.

The Crown's experts disputed the schizophrenia diagnosis and said Magnotta's behaviour is better explained by antisocial, histrionic, narcissistic and borderline personality disorders that would not necessarily have rendered him incapable of knowing that what he was doing was wrong.

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The members of the jury spent 10 weeks in a Montreal courtoom listening to and viewing the often gruesome details of the crimes Magnotta is accused of. (Mike McLaughlin/Canadian Press)

The fact that jurors on Tuesday asked the judge to clarify whether a personality disorder is a disease of the mind, i.e. a mental disorder, could be an indication that they are trying to decide among themselves which diagnosis is most credible, Baillie said.

"If you see this as an individual who had schizophrenia and was acting in response to some distorted perceptions, then the NCR verdict fits. If you believe this was a person who knew exactly what he was doing and made choices to do it anyway and that that is part of his personality disorder, then NCR doesn't fit," he said.

Vancouver defence attorney Deanne Gaffar, who has worked on many NCR cases, thinks the jurors' question to the judge could be a sign that they are struggling to understand the differences between the two kinds of mental disorders and that they do not wholly accept the prosecution's portrayal of personality disorders as mental disorders that don't meet the conditions of an NCR defence.

"People could be starting to be concerned [and asking]: Have we understood this? Is this really a mental disorder? If it's a mental disorder, doesn't that, too, qualify as one of the factors under Section 16?" she said.

"They have to sort through the expert evidence to determine what is a person like when they have a personality disorder and can you reach the stage of automatism that would be necessary to make a finding of not criminally responsible." 

2. Understanding the 'balance of probabilities'

In NCR cases, the jury doesn't need to be convinced beyond a reasonable doubt that the defendant was suffering from a mental disorder that rendered him incapable of appreciating the nature of the act or knowing it was wrong. Rather, the standard of proof is something known as a "balance of probabilities." But it can be a challenge for jurors to assess what exactly that means, and that might be another aspect holding up the Magnotta verdict, Gaffar said.

"It's hard for a jury to conceptualize the standard of a balance of probability. It really means 'more likely than not,' but for jurors, it's a murder case, it's a horrific murder case, so they might be reluctant," she said. "They might have problems with the concept that if someone has a mental disorder that affected them to the requisite extent, they have to find him not criminally responsible."

3. Misconceptions about the consequences of an NCR verdict

Even though the NCR defence has deep roots in the British common law system, Gaffar says there are still many misconceptions about mental illness and about what it means to find someone not criminally responsible, especially when the crime in question is a violent or particularly gruesome one as in Magnotta's case.

'A lot of people believe that … having this option for not criminally responsible is somehow not proper and that people are getting away with murder.' - Deanne Gaffar, defence attorney

"A lot of people believe that … having this option for not criminally responsible is somehow not proper and that people are getting away with murder," she said.

"They have a very Hollywood view of what someone in the throes of psychosis is supposed to look like."

Some of those misconceptions could be what's delaying deliberations, Gaffar said.

A lack of understanding about what happens to defendants who are found not criminally responsible could also be giving jurors pause, said Greg Brodsky, a veteran Winnipeg lawyer who has won two landmark NCR cases before the Supreme Court of Canada.​ 

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Lin's father, Diran Lin, was in the courtroom for much of the trial and saw much of the same disturbing evidence that the jury did. (Ryan Remiorz/Canadian Press)

"They may think if he's found NCR that they'll let him go after he's treated — give him a pill and send him on his way," he said.

Even though the judge has instructed jurors that the matter of sentencing is in the hands of the court and is not something that should factor into their deliberations, some might fear that an NCR verdict could mean that a dangerous individual would be released into the community and not realize that a review board must assesses whether the person poses a threat to public safety, Brodsky said.

"They might not appreciate that if he's found not criminally responsible, they have to have a hearing to determine if he's presently dangerous," he said. 

4. Multiple charges

Magnotta faces four other charges aside from murder, including criminally harassing Prime Minister Stephen Harper and other members of Parliament, mailing obscene and indecent material, publishing obscene materials and committing an indignity to a body. To find him not criminally responsible for Lin's homicide, the jury has to find the same on the four other charges as well.

"There can't be inconsistent verdicts​," said Brodsky.

Baillie said that while the large volume of graphic video evidence and expert testimony presented over the course of the 10-week trial might have convinced some jurors that Magnotta was in a psychotic state when he killed Lin, it might be harder to make that same determination about some of the other acts he is accused of, such as mailing letters and body parts to schools and members of Parliament or uploading videos to the internet.

"The judge's instruction was you have to find NCR on all five, [and some jurors might be thinking] 'I thought we found it on the homicide, but I can't find NCR on mailing the packages or posting the video,'" Baillie said.