OTTAWA -- Closing arguments have begun in the trial of an Ottawa police officer charged with manslaughter in the fatal arrest of Abdirahman Abdi nearly four years ago.

The arguments were initially scheduled to be heard in April, but proceedings were interrupted by the COVID-19 pandemic.

Crown and defence attorneys will be presenting their closing arguments via Zoom video conferencing over the next three days.

Montsion has pleaded not guilty to charges of manslaughter, aggravated assault and assault with a weapon.

What is being alleged?

Ottawa defence lawyer Michael Spratt, a partner at Abergel Goldstein & Partners, tells CTV Morning Live that the Crown is attempting to prove that Montsion's actions that day killed Abdi.

"The Crown is alleging that Constable Montsion used unreasonable and excessive force in facilitating the arrest of Mr. Abdi. What they have to prove is that the violence that this police officer used was a substantial and contributing cause to Abdirahman Abdi's death and they have to prove that beyond a reasonable doubt," Spratt said. "They have to prove that that bodily harm was a significant reason why Mr. Abdi passed away."

Spratt--who is not involved in this case--says there is heavy burden on the Crown, and that will be the focus of Montsion's defense.

"They're going to say that, beyond a reasonable doubt, it hasn't been shown that that's the case," Spratt says. "They go a step farther. They say Constable Montsion was using reasonable force and they deflect a little bit and say that the injuries that Mr. Abdi suffered were delivered by another officer, [Const. Dave] Weir in this case."

Weir was never charged in connection with Abdi's death.

Spratt says because written arguments were submitted months ago, the court might be in a position to deliver a verdict sooner than what might be expected in a case such as this.

"There still is a lot of evidence to go through and to dissect here, as well as some complicated legal arguments when you're dealing with police officers and use of force," he said, "but this case has played out over the last four years. Written arguments were delivered to the judge months ago so, because of the delay getting to this point, the fact that the judge has had these written closing arguments, the court might be in a position a bit sooner than we might normally expect to finally deliver a verdict and put an end to this stage of the litigation."

Day one arguments: defence asks judge to rely on CCTV footage

In their closing arguments Monday, Montsion's defence counsel argued that the officer's actions were justified and called for an acquittal on all charges.

Arguments by the Defence rely heavily on CCTV footage of Abdi's arrest outside his Hilda Street apartment building and on the information Const. Montsion had in the moments before he arrived on scene.

The Defence played several audio recordings of the Ottawa police dispatcher, which reported a male suspect had been thrown out of the Bridgehead coffee shop for allegedly grabbing women's breasts and was reportedly violent with people outside. Audio clips of Const. Weir's response were also played, in which Weir states he pepper sprayed the suspect to no effect.

Lawyer Solomon Friedman argued that police training would have required Montsion to intervene in the way he had, given the information available that the suspect had assaulted people and was violent.

Following the audio recordings, Friedman moved on to the CCTV camera footage that shows Montsion's actions during the arrest, going through it frame by frame. The defence is arguing that the video footage is more reliable than eyewitness testimony.

The Defence argues Montsion assessed the scene upon arrival and took cues from Weir on what to do next, adding he had a duty to intervene.

Justice Robert Kelly asked about Montsion's blows at one point of the video. He asks where the blows landed so that he may compare that with eyewitness testimony, adding he must consider all evidence presented to the court. The Defence says the blows were directed at the face, but questions the amount of force with which they landed.

Day two arguments: defence point to medical conditions as Crown brings up plated gloves

On day two of closing arguments, Const. Montsion's defence team argued it was not the officer's actions that lead to Abdi's death, but a combination of multiple factors including an underlying heart condition and something called 'excited delirium.'

"This is a case where there were numerous independent physical and emotional stressors acting on Mr. Abdi that each independently could have caused his death," Friedman said.

The Crown contends it was Montsion who caused Abdi's broken nose, using what they called 'hard knuckle-plates gloves.'

"Even if you have some hesitation, even if you want to rely on the interpretation of the frame-by-frame (video footage of the arrest) that is urged upon you by the defence, in our submission, the force used in responding to it is over the top," said Crown attorney Phil Perlmutter. "There is no evidence that supports a reasonable belief to believe that it was necessary to use force likely to cause grievous bodily harm."

The Defence said the gloves were part of Montsion's uniform and were purchased by his supervisor.

Citing medical evidence by Dr. Christopher Milroy that said Abdi's facial injuries were more consistent with a fall than a blow, defence attorney Michael Edelson said, "It's supported by the video evidence, your Honour. We see the directionality in which his face goes down. It makes entirely not only common sense but scientific sense."

Edelson also picked apart Const. Weir's testimony. Edelson said Weir testified he did not recall kicking Abdi because it didn't happen, adding video evidence showed it had. "This is troubling to say the least with respect to the reliability of this witness and his testimony."

Closing arguments end Wednesday.