TORONTO -- The man who killed 10 people after deliberately driving down pedestrians in Toronto told a psychiatrist he knew what he did was wrong, court heard Friday.

"I know what I did was morally wrong," Alek Minassian told Dr. Alexander Westphal, a U.S. based psychiatrist retained by the defence.

"And extremely devastating. And irreversible."

Those words were not captured in Westphal's final report, Crown attorney Joe Callaghan said.

Westphal has said Minassian lacks empathy and does not understand the moral wrongfulness of killing 10 people, but said criminal responsibility is a legal opinion, not a psychiatric one.

The 28-year-old from Richmond Hill, Ont., has pleaded not guilty to 10 counts of first-degree murder and 16 of attempted murder. The defence argues he is not criminally responsible for his actions on April 23, 2018.

Minassian's state of mind at the time is the sole issue at trial after he admitted to planning and carrying out the attack.

Callaghan alleged the star witness for the defence purposefully left out the admission by Minassian "because it did not fit" Westphal's narrative.

Westphal denied the charge, saying he synthesized information from various sources, including his hours of interviews with Minassian.

In a report, Westphal concluded:

"The act was also completely beyond his comprehension given his absence or understanding of emotional nuance, social exchange, and contextual accommodation," he wrote.

"He had absolutely no insight into the terrible impact that the act would have on other beings, and did not think about the pain he was bound to cause, nor understood it, even slightly, now."

Callaghan took issue with the conclusion.

"How can you testify in this court in this trial on mass murder and leave out 'It was extremely devastating and irreversible'?" Callaghan said.

The prosecution pointed it out it never would have known about Minassian's statement if Justice Anne Molloy didn't order videos of the interviews released to the Crown two weeks ago.

Minassian's lawyer had said Westphal would be the only expert to say Minassian should be found not criminally responsible for his actions due to autism spectrum disorder, but the psychiatrist has stopped short of making that conclusion.

Earlier, Westphal conceded Minassian has shown empathy in some instances.

Under cross-examination from the prosecution, Westphal said Minassian showed a touch of empathy for his father in his police interview.

About nine hours after the attack, Det. Rob Thomas had a long interview with Minassian.

At one point, Thomas confronts Minassian after catching him in a lie.

Minassian initially told the detective he had taken the bus to the Ryder rental agency to pick up the van.

But his father actually dropped him off at a coffee shop and then Minassian walked four kilometres to the rental agency, court has heard.

Minassian told the detective he lied in order to protect his father, worried he'd be charged as an accessory to murder.

His father, Vahe Minassian, did not know about his son's plans for the attack, court has heard.

"Do you agree Mr. Minassian lying to protect his father shows his ability to take perspective and have empathy for his father?" Callaghan asked.

"That statement is too general for me -- to some degree it does, but I don't think that requires much sophistication in this context, but I will grant you it does require reference to his father's needs as opposed to his own needs, which is unusual for him," Westphal said.

In that police interview, Minassian also refuses to name or discuss anyone else, including his parents or family members.

Callaghan suggested that meant Minassian didn't want to involve others, demonstrating "his ability to have empathy and take the perspective of others and respect their privacy" -- assertions Westphal agreed with.

The psychiatrist, who specializes in autism, maintains that despite some examples of empathy, Minassian does not understand that other people have feelings.

Westphal has previously testified that Minassian views people as objects and does not comprehend the devastation of his actions.

He has also said Minassian does not understand what he did was wrong, despite the young man telling the doctor repeatedly he did.

He has concluded that Minassian was incapable of rational decision making at the time of the attack based on his irrational thoughts due to autism spectrum disorder.

This report by The Canadian Press was first published Dec. 4, 2020.