FREDERICTON -- Lawyers for Matthew Raymond acknowledge their client shot and killed two Fredericton police officers and two civilians on Aug. 10, 2018, but they say he was not criminally responsible because of a mental disorder.

The admission was made Tuesday morning as Raymond's trial on four counts of first-degree murder opened in Fredericton.

"We agree that on that day, Matthew Raymond shot and tragically killed Bobbie Lee Wright, Donnie Robichaud, Constable Sara Burns and Constable Robb Costello," defence lawyer Breana Vandebeek said.

She said they made the admission because "it's the truth" and it will reduce the number of people who would need to testify and relive the events of that morning.

"It helps you focus on the real issue in this case, which is Mr. Raymond's state of mind at the time of the shooting," Vandebeek said in her opening remarks to the jury. "That is, whether or not he is not criminally responsible for reason of mental disorder."

Raymond pleaded not guilty to the charges as they were read. Otherwise he sat quietly inside the convention centre ballroom that has been converted into a courtroom to allow for adequate physical distancing.

Even the members of the seven-woman, five-man jury sat two metres apart from each other. The province has said Raymond's trial is the first full jury trial in Canada since the COVID-19 pandemic began.

Crown prosecutor Jill Knee used her opening statement to detail the events of the morning of the murders.

"On Aug. 10, 2018, the accused started shooting a little after seven in the morning," she said. "Approximately 37 minutes later, the shooting stopped. At the end of those 37 minutes, four victims lay dead in the parking lot at 237 Brookside Drive, and Fredericton police had shot the accused once through his apartment window."

The Crown says the killings were planned and deliberate, and it plans to call 39 witnesses during the trial, which is expected to last four weeks.

Knee said Robichaud was shot five times, Wright was shot twice, Costello was shot four times and Burns was shot twice.

All victims were hit at least once in the head, and one of the shots pierced Costello's bullet-resistant vest.

Knee said investigators seized a semi-automatic rifle and a 12-gauge shotgun from Raymond's apartment. They found 22 spent casings and seven spent shotgun shells in two different rooms. There were also close to 2,000 live rounds of ammunition in the apartment, she said.

She said the jury will see video from July 25, 2018 that shows the accused complaining about noise around the apartment.

The defence said Raymond was delusional and paranoid at the time of the crimes.

"On Aug. 10, 2018, Matthew Raymond suffered from a mental disorder, and that mental disorder made him either incapable of appreciating the nature and consequences of his actions, or of knowing that those actions were wrong," Vandebeek said.

She said at the time, Raymond was making all kinds of strange calculations and biblical references -- often using the numbers 33 and 666.

She said in the year or two leading up to the shooting, Raymond had withdrawn from his family and his mental health was on the decline.

"He became fixated on issues that were previously unimportant to him -- things like religion and politics," Vandebeek said. "He would spend hours on the computer obsessing over conspiracy theories. No one realized the extent of what was going on."

She said in the days prior to the shootings, the delusions had taken over.

Vandebeek said Raymond felt people were after him and pounding on his walls, and he had delusions of a child in the courtyard taunting him.

"He was panicked, scared and frightened," she said.

Justice Larry Landry of the Court of Queen's Bench told the jury at the start of the trial that the Crown must prove its case beyond a reasonable doubt. "You are the sole judges of the facts," he said.

Tuesday afternoon was spent cataloguing exhibits that will be presented during the trial, including the SKS semi-automatic rifle and shotgun seized from Raymond's apartment.

The trial continues Wednesday.

This report by The Canadian Press was first published Sept. 15, 2020.