A man accused of shooting an Abbotsford, B.C. police officer in 2017 says he's not guilty of first-degree murder.

Oscar Arfmann entered the plea in a New Westminster courtroom Monday morning at the start of a judge-only trial expected to last about two months.

The 67-year-old is charged with the first-degree murder of Const. John Davidson, who died while responding to reports of a stolen vehicle on Nov. 6, 2017.

Davidson, 53, was among the first to arrive at a strip mall on Mount Lehman Road when a member of the public reported he'd blocked a stolen truck from leaving the parking lot.

The gripping details of what happened in the moments leading up to Davidson's death were the focus of the Crown's opening statement Monday.

Arfmann sat and listened, as did Davidson's family and former partner, as counsel outlined what it claims happened that day.

Davidson had been driving an unmarked police cruiser when he heard reports of shots fired at the shopping complex.

Unable to drive away, a man police allege was Alberta resident Arfmann waited for police to arrive at the scene. The Crown said witnesses reported he told those in the lot that "they would see what he would do to the cops when they got there."

According to the Crown's statement, Arfmann shot Davidson when the constable reached the scene.

"Within moments of getting out of his police vehicle, Const. Davidson was ambushed by the accused," prosecutor Theresa Iandiorio told a B.C. Supreme Court.

"Const. Davidson fell face first on the ground. He did not move. He began bleeding."

Arfmann is alleged to have walked over and shot Davidson again as he lay on the ground.

The suspect was arrested near the scene, following a chase that ended in a crash and more gunfire. The Crown is convinced that police found the weapon used in the crime inside the vehicle Arfmann was driving.

It is alleged Arfmann's vehicle, a stolen black Mustang, also contained several knives and ammunition for the rifle.

Arfmann has been charged with first-degree murder, a term typically defined as a planned and deliberate killing, but that also includes when the victim is a police officer. 

The Crown's focus for the high profile trial is to prove Arfmann was the one who pulled the trigger. The prosecution service plans to call as many as 30 witnesses to the stand during the next eight weeks.

In a statement, the Abbotsford Police Department said a number of citizens and police officers are expected to testify.

"The trial will move the entire community into another phase of healing," it said.

Speaking to reporters outside the courtroom, Abbotsford Police Insp. Tom Chesley said it was "obviously difficult for any of us to hear the evidence and see as the witnesses say what they saw.

"Clearly we have waited a long time for this trial to start - for it to get going - for the police department, for the city of Abbotsford, all the citizens, certainly the Davidson family. It's good to get it going."

In the days following his death, Davidson's coworkers and family members described the fallen officer as a hero. Thousands attended his funeral

Arfmann is being represented by lawyer Martin Peters, an experienced criminal defence lawyer who is also representing Gabriel Klein, a man charged in the stabbing death of an Abbotsford high school student.

None of the allegations have been proven in court.

With a report from CTV News Vancouver's Emad Agahi in court and The Canadian Press