NEW WESTMINSTER, B.C. -- An Alberta man found guilty of the first-degree murder of an Abbotsford police officer will be criminally sentenced, despite a recent psychiatric assessment which suggested he may have been not criminally responsible at the time, according to his defence lawyer.

In October, 67 year-old Oscar Arfmann was found guilty in the 2017 shooting death of Const. John Davidson at a shopping complex on Mount Lehman Road.

However, the conviction was not entered into the court record, as Justice Carol Ross granted a defence request for a new psychiatric assessment.

Arfmann's lawyer, Martin Peters, told CTV News Vancouver the results of that assessment were delivered at the end of November.

"It said that, given the totality of evidence, that there is a likelihood or possibility that at the time that Mr. Arfmann killed Const. Davidson, Mr. Arfmann did not understand that what he was doing was wrong," Peters said.

However, Peters said Arfmann has instructed his lawyers he doesn't want to pursue an NCR (not criminally responsible) finding, and instead wants to be sentenced. Peters said Arfmann has not offered an explanation as to why.

"Mr. Arfmann made it very clear to us that he is not crazy. He did not want to be found not criminally responsible by reason of mental disorder," Peters said. "The difficulty for us is that even though we may have a different opinion, we are obliged to follow his instructions, and it's challenging in this case."

Peters said the doctor's finding pertains to various statements Arfmann made throughout the psychiatric assessment, including "his belief that the RCMP was being overtaken by the Russian mafia."

At a hearing in New Westminster Supreme Court on Monday, Ross ruled the case will proceed to sentencing, and set the date for Feb. 3.

A first-degree murder conviction means an automatic life sentence, with no possibility of parole for at least 25 years.

During Monday's hearing, prosecutor Wendy Stephen also requested to go ahead with sentencing, calling it an "unusual situation."

"It's the Crown's submission that for the court to go behind the decision is potentially to interfere in the ability of an accused person to decide his own fate. This is all premised, of course, on an accused person being fit," Stephen told the court.

Stephen argued the doctor who conducted the assessment "speculated" when he found Arfmann may have failed to contemplate the moral wrongfulness of his actions, and added Crown is of the view that the requirements for NCR would not be met.

"Only Mr. Arfmann could know what was in his mind when he murdered Const. Davidson," Stephen said.

Arfmann did not testify during the trial, and the defence did not present a case.

Davidson was fatally shot in the line of duty on Nov. 6, 2017. The court heard police were called after employees of a local car dealership recognized a vehicle that had been stolen from their lot days earlier.

One of the workers testified he was confronted by Arfmann, and told him the police were on their way.

He testified Arfmann responded: "I'll show you what I have in store for the police."

The court heard shots were fired at a truck blocking the stolen car.

Davidson was one of the officers responding to 911 calls about the incident, and was the first to arrive on scene. He was shot twice from behind.

Arfmann was arrested after police rammed the stolen Mustang he was driving not long after the killing. Officers found a rifle on the passenger seat.