Matthew de Grood told psychologist he would have killed more partygoers

Matthew de Grood told a psychologist if there had been more people at the Calgary party where he fatally stabbed five young people, "unfortunately they would have been terminated as well."

The 24-year-old, who is being tried on five counts of first-degree murder, described the stabbings, "including how people fell to the ground," for forensic psychologist Andrew Haag, who testified today at de Grood's trial in Alberta's Court of Queen's Bench.

Haag, who was the final witness on Day 4 of the trial, works at Alberta Hospital in Edmonton and estimated he spent about 20 hours with de Grood before diagnosing him with schizophrenia.

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De Grood has admitted to stabbing ​Lawrence Hong, 27, Joshua Hunter, 23, Kaitlin Perras, 23, Zackariah Rathwell, 21, and Jordan Segura, 22, at a party in the Brentwood neighbourhood on April 15, 2014. But he pleaded not guilty to the murder charges.

The five were stabbed around 1:30 a.m. There were about 25 people at the peak of the party and, once a group left for McDonalds, only about six or seven remained, according to an agreed statement of facts read in court Monday.

De Grood's lawyer, Allan Fay, is mounting a not criminally responsible (NCR) defence, presenting evidence that de Grood did not know at the time of killing that what he was doing was morally wrong.

"I'm happy with the way the evidence came out," said Fay. "I think the experts who testified certainly support my position that my client was not criminally responsible at the time these events occurred."

All three experts testified that in their opinions, de Grood is not criminally responsible for the stabbing deaths. Still, no matter the judge's decision, Crown prosecutor Neil Wiberg says no outcome will bring the victims back.

 "Everybody's a loser in this particular case," said Wiberg. "Five outstanding people were killed and nothing, no decision will get around that."

Haag testified that de Grood did suffer from a "disease of the mind" at the time of the killings, which "interfered with his ability to appreciate the moral wrongness of his actions."

Voices told de Grood to kill

In testimony Wednesday, court heard that de Grood reported hearing voices telling him to kill and believed the end of the world was coming before he grabbed a knife from the kitchen and stabbed his victims to death.

Crown prosecutor Stephanie Brown asked whether de Grood could have been faking or exaggerating his symptoms.

"It's possible, it's just unlikely," Hagg testified, saying the totality of evidence led him to believe de Grood was not faking a mental disorder.

Haag testified that the information he used in making his diagnosis came from his interviews with de Grood and from independent sources such as text messages, Facebook posts, friends and parents, who "largely did not communicate with each other."

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If de Grood is found NCR by the judge hearing the trial, then he would be sent to a psychiatric facility rather than a prison.

The Alberta Review Board would then be tasked with reviewing de Grood's treatment and progress annually to determine what, if any freedoms he would be allowed, including if he's released back into the community.

It is possible de Grood could spend his life in custody.

"No one can say," said Fay. "Months, years, maybe the rest of his life. One never knows."

Closing arguments will take place on Tuesday. 

It's not known when Justice Eric Macklin will make his decision.

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