Moss in 'cannabis-induced' psychotic state when he killed girl: forensic psychologist

Long-term, frequent cannabis use played a role in the mental condition of the man who admitted to killing seven-year-old Bella Desrosiers with a pair of scissors, an expert in forensic psychology testified in court Tuesday.

David Moss was in a psychotic state induced by the drug the night of the attack in May 2020, crown witness Dr. Andrew Haag said. But Haag still believes Moss had an understanding of what he was doing.

"He’s able to comprehend…'I am going to do something…that is at very least illegal… (something) others wouldn’t condone,'" Haag told court.

Moss told an Edmonton Police Service detective the day after Desrosiers was killed that he was hearing voices and undergoing an “awakening” at the time.

The accused added that he had to play out his fears and kill the girl, according to EPS video of the interview.

"Everything’s an illusion and like, the past and the present don’t exist. Time doesn’t exist," Moss said.

Haag told the court that he couldn’t confirm whether or not everything Moss said he was experiencing was real or fake. The doctor said he tested Moss to ascertain whether or not he was malingering, but that test was indeterminate.

Haag cited Moss' early introduction to cannabis, his years of cannabis use, and his own reporting that he tripled his consumption during the pandemic as factors.

Haag said while the accused may have believed he was in other worlds, Moss had an understanding of the impact of his actions when he attacked Desrosiers.

“Even if you thought he was in these realities…he was able to engage in the naturalistic world,” Haag stated.

The detective in the video asked Moss if he "second guessed that intuition" to kill Desrosiers in her home.

"Yeah. Of course I did. You think I wanted to do this?" Moss responded.

"You had to do it? You didn't have a choice?" the detective pressed.

"This is the whole point," Moss agreed.

The defence has put forward its own expert, Dr. Marc Nesca, who believes a brain injury that Moss suffered nearly 20 years ago may have caused him to believe in alien abductions, COVID-19 conspiracies, and voices in other dimensions compelling him to take action.

It's Nesca's contention that Moss is not criminally responsible due to a mental disorder.

With files from CTV News Edmonton's David Ewasuk