FREDERICTON -- Members of an RCMP team who responded to a mass killing in Fredericton two years ago told jurors Thursday about the moment they entered the suspect's apartment and wrestled away his gun.

"I thought one of us was going to get shot," Cpl. Jean-Francois Comeau told the courtroom.

He was one of three officers who testified Thursday at the trial of Matthew Raymond, who is charged with first-degree murder in the shooting deaths of Donnie Robichaud, Bobbie Lee Wright and Fredericton police constables Robb Costello and Sara Burns, on Aug. 10, 2018.

The defence has admitted that Raymond, 50, killed the victims, who were shot in the parking lot of an apartment complex, but says he should be found not criminally responsible because of a mental disorder.

The RCMP emergency response team was called to the scene at 237 Brookside Dr. after the four victims had been killed by a shooter positioned in a third-floor apartment.

Cpl. Mark Simon told jurors that when he arrived, police had already used a sledgehammer to punch holes into the door of the shooter's apartment. He said he used a chainsaw to remove the door.

"Things were moving very fast," Simon told the court.

By this time, Raymond had been shot in the abdomen by a police officer outside the building.

Cpl. Jeremy Harding testified that he deployed a robotic, camera-equipped vehicle inside the shooter's apartment, which showed an image of the suspect on the floor and pointing a rifle toward the doorway.

"One hand was on the stock and the other was on the barrel," Harding told jurors.

He said officers were yelling from outside the apartment: "This is the police! We're outside in the hallway. Give yourself up. Drop the gun! Drop the gun!"

Harding said he was aware of the risk to his own life. He said he positioned his body against an outside wall so his body armour would, "soak up any rounds that were fired at me from the apartment."

Harding said he saw on the video monitor that the suspect was trying to throw items at the robot. He said Raymond took his hands off the gun, and that's when he instructed other officers to storm the apartment.

Comeau told the jury he and other officers climbed over debris used to barricade the door and went into the living room.

"I saw the suspect still holding the rifle, turning it towards us," Comeau said. "The last thing I remember is seeing the gun barrel being pointed right to me."

He said he was holding his ballistic shield as he jumped on the suspect and started punching him in the head until other officers had the suspect restrained and the weapon removed.

"To my surprise, he was still fighting us," Comeau told the jury.

Simon said he grabbed the rifle. Harding said Raymond appeared to be reaching for a "sizeable knife" but Harding was able to get to it first.

The court also heard from four registered nurses who attended to Raymond in hospital.

Melanie Harris said in the hours after Raymond arrived at hospital, he had a breathing tube so he was unable to speak, but he wrote a note to say he wanted to speak with a lawyer.

Denise Green, Reanne Allain and Nelly Clark all described Raymond as being calm, polite and co-operative.

Allain and Clark confirmed that Raymond had been prescribed Haldol. That is the brand name for Haloperidol -- an antipsychotic drug often used to treat schizophrenia, delirium and hallucinations. They said the medical file indicated it was to be given intravenously every four hours as needed.

The trial continues Friday.

This report by The Canadian Press was first published Oct. 1, 2020.