Jury deliberations have begun in the trial of a man accused of fatally running over a Toronto police officer, with the judge providing guidance to them, including that the Crown prosecutors have no evidence that "fully supports" their case.

Ontario Superior Court Justice Anne Molloy told jurors on Thursday that the police officers’ testimony that is the foundation of the case against Umar Zameer doesn`t match the physical evidence, and advised them to watch out for possible collusion that might misrepresent how Det-Const. Jeffrey Northrup died.

“There is no evidence that fully supports the Crown’s theory,” said Justice Molloy. “It is clear from the video that Officer Northrup was not standing upright in the laneway when he was knocked to the ground and run over, even though the three police witnesses all say that he was.”

“When three versions of the event are wrong, and wrong in the same way, you must also consider whether there has been collusion between those witnesses. All of the officers denied collusion,” she said.

Presented with a transcript of the judge’s remarks, criminal lawyer Joseph Neuberger, who is not connected to the case, said that hearing this guidance from an impartial judge tips the scales heavily in favour of the defense.

“Her honour’s particular comment about that portion of the evidence for the Crown is extremely damaging to the Crown’s case. And I mean, extremely damaging,” he said in an interview.

Zameer has pleaded not guilty to first-degree murder in Northrup's death. The officer, who was in plain clothes, died on July 2, 2021, after he was hit by a vehicle in an underground parking garage at Toronto City Hall.

Prosecutors say Zameer made deliberate choices to drive dangerously while there were people nearby, killing the officer. They allege Zameer drove directly at Northrup, who they say was standing at the time.

The defence argued Zameer did not intend to kill anyone and behaved reasonably in the face of what he thought was an imminent threat to his family as two unknown people rushed up to his car and began banging on it.

Zameer testified he did not see anyone in front of his car as he was driving forward. Two crash reconstruction experts, including one called by the Crown, told the court they concluded Northrup fell after the car made glancing contact with him while reversing, and was on the ground when he was run over.

The expert called by the defence said Northrup would have been in the car's blind zone and not visible to Zameer when on the ground.

Molloy told jurors there are three pivotal issues in the trial: whether Zameer knew Northrup was a police officer acting in the course of his duties, whether Northrup was standing in front of Zameer's car when he was hit, and whether Zameer knew he had run someone over.

Molloy told the jury there are four possible verdicts in the trial of Umar Zameer: first-degree murder, the lesser included offences of second-degree murder or manslaughter, or not guilty of any offence. She said that in order to find Zameer guilty of murder, jurors must find beyond a reasonable doubt that he intentionally ran over Northrup.

Whether it is first- or second-degree murder depends on whether jurors believe beyond a reasonable doubt that Zameer knew Northrup was a police officer acting in the course of his duties.

Under law, the murder of a police officer acting in the course of their duties is automatically first-degree, so long as the person accused knew or was wilfully blind to that fact.

The jury began deliberations on Thursday at about 5:30 p.m.