THUNDER BAY, ONT. -- A clear link between the injury an Indigenous woman suffered when struck by a trailer hitch and her eventual death months later establishes the guilt of the man accused of killing her, regardless of her underlying health conditions, a Crown attorney said Thursday in his closing arguments.

Brayden Bushby's manslaughter trial in Thunder Bay, Ont., which began Monday, was centred on whether the evidence would prove that the man's actions contributed to the death of 34-year-old Barbara Kentner.

Bushby, 22, has admitted to throwing the trailer hitch at Kentner in January 2017, pleading guilty to aggravated assault. But his lawyer has argued his client is not guilty of manslaughter in the woman's death five months later.

Crown attorney Andrew Sadler pointed Thursday to a forensic pathologist's testimony that an abdominal infection stemming from a small bowel rupture, caused by the assault with the hitch, "hastened" Kentner's death, although she had an underlying illness that contributed.

"It may be that someone who was healthier would recover from the same injury. That doesn't change Mr. Bushby's culpability," Sadler told court.

He said the Crown does not have to prove Bushby's act was the only cause of Kentner's death, just that it was a significant factor, and he argued Dr. Toby Rose's testimony proved that argument beyond a reasonable doubt.

Witnesses who were with Bushby when the assault happened testified that he was drunk at the time and laughed after he threw the hitch. Melissa Kentner, the victim's sister, has testified she remembered someone hanging out of a vehicle saying "I got one" after her sister was hit.

Bushby's defence lawyer George Joseph has argued that there is no legal link between the assault and Kentner's death months later.

During his cross-examination of Rose, who performed the autopsy on Kentner, Joseph referenced Kentner's medical history, arguing that she could have died on the same date from liver disease.

Rose agreed with Joseph that another professional might have come to a different conclusion about Kentner's cause of death, but stood by her assessment that Kentner died when she did because of the trailer hitch injury.

Joseph argued on Thursday that while he's "certain" that his client threw the hitch at Kentner, he can't know for sure that Bushby's conduct is the reason she died.

"What I am uncertain of is what finally took Barbara Kentner's life. I don't know what killed her, and at the core of it, neither does Dr. Rose," Joseph told court.

The Crown cited the "thin skull" legal principle, meaning that Bushby is still culpable for the outcome of his actions even though Kentner was sick with liver disease and more likely to die from her injury.

Sadler encouraged Justice Helen M. Pierce to pick up and hold the heavy trailer hitch that was submitted as evidence at the trial to consider the foreseeable outcome of throwing it at a person.

"In my submission there isn't anything that has happened in this case that would remove Mr. Bushby's moral culpability," Sadler argued.

Bushby had been charged with second-degree murder after Kentner died, but it was later changed to manslaughter and aggravated assault.

Sadler told court this week that the indictment was changed because of space limitations in Thunder Bay that made a jury trial impossible in the city during the COVID-19 pandemic.

He said it was a priority for the trial to proceed this fall, and that the "only way" for that to happen was to have a trial by judge alone, which "could not happen, in this case, on the charge of murder."

The judge is expected to deliver the decision on Dec. 14.

This report by The Canadian Press was first published Nov. 5, 2020.