FREDERICTON -- The mother of Fredericton mass shooter Matthew Raymond says he constantly talked about conspiracy theories and she tried to convince him to see a doctor.

Shirley Raymond took the stand Monday as a defence witness at the trial of her son on four counts of first-degree murder.

The defence and Crown agree that Matthew Raymond killed Donnie Robichaud, Bobbie Lee Wright and Fredericton police constables Robb Costello and Sara Burns in August 2018 and that he had a mental illness.

The defence is trying to prove he should be found not criminally responsible because the mental disorder rendered him incapable of appreciating the nature of his actions and that they were wrong.

His mother told the court that in the year before the shootings, her son believed in demons and that the end of the world was coming.

"He was paranoid. He wouldn't talk on the phone. He thought all phones were tapped," she said.

Raymond said if she was watching TV, her son would say she was watching fake news, that mass shootings such as those in the United States never actually happened and the victims were just actors.

"You need to go to your doctor. You're sick," his mother said she told him repeatedly. She said he refused to get help and replied that she was the one who was sick.

She said her son had begun to stockpile food because he thought the end of time was coming and they needed to be prepared, and that included being able to go to the woods to hunt for sustenance.

Raymond said she began to avoid conversations with her son. "There was no conversation," she said. "I listened. He could talk for hours. I could not change his mind."

She said she thought his condition was getting worse and she threatened to call police, but he said if she did, then he would never talk to her again. She said she then decided that he hadn't done anything illegal and the police probably couldn't intervene.

The witness said her son stopped listening to music and watching TV because he thought it was full of subliminal messages of evil.

She said she saw him about 10 days before the shootings when he came to her apartment and was upset with his bank. She said they had a new security protocol and he was having trouble with a password. She said it was hot and humid in her apartment and she said she couldn't deal with any more of his problems.

On the morning of Aug. 10, 2018, she heard about the shootings on the news and tried calling her son to tell him to stay safe. But she said it never crossed her mind that he was the suspect.

She told the court she saw her son in custody on a number of occasions and spoke with him almost daily by phone when he was in jail. "He was difficult to talk to," she said. "He didn't make sense a lot of the time."

She said Raymond gave her a note with his ideas for a large cast iron stove that he wanted to have patented, and he became very upset when she gave the note to his lawyer.

Under cross-examination by Crown prosecutor Darlene Blunston, Raymond said she started to see the changes in her son in 2017. She said he wasn't angry but did act more religious.

She is expected back on the witness stand as the trial continues Tuesday.

This report by The Canadian Press was first published Oct. 26, 2020.