A Minneapolis police officer who shot and killed an unarmed woman who approached his squad car minutes after calling 911 was caught up in “a perfect storm” of events but “acted as he was trained”, his attorney argued on Monday.

Prosecutors countered that Mohamed Noor was responsible for “a tragic event of his own making” in 2017 when he shot Justine Ruszczyk Damond, a dual US-Australian citizen who had summoned police when she heard a possible rape in the alley behind her home.

The case went to the jury almost a month after jury selection began. Noor, who was fired after he was charged, faces two counts of murder and one of manslaughter. The jury is sequestered until reaching a verdict.

Noor’s lawyer, Thomas Plunkett, launched his closing address by banging on his lectern, shouting a profanity and yelling, “Pow!”

Plunkett was recreating testimony from Noor that he heard a loud bang right before Damond approached his squad car, which was followed by his partner swearing and struggling to pull out his gun, right before Noor fired.

“It’s the perfect storm,” the lawyer said. “That is the whole case.”

He urged jurors to avoid looking at the shooting with hindsight and to consider whether a reasonable officer confronted by the same factors as Noor would do the same.

“Mr Noor acted as he was trained,” Plunkett said. “He acted as a reasonable police officer.”

Earlier, the prosecutor, Amy Sweasy, urged the jury to find the opposite.

She again questioned Noor’s claim that he and his partner, Matthew Harrity, had heard a loud noise, and that Noor had feared an ambush just before a woman appeared at Harrity’s window. Noor testified that he had seen a woman raise her arm and he had fired to save Harrity’s life.

Sweasy reminded jurors of the chaotic aftermath of the shooting, with responding officers trying to figure out what had happened. She said that’s when the “loud bang” emerged, calling it a theory that had taken on a life of its own.

She noted that neither Noor nor Harrity had mentioned it at the scene, with Harrity first talking about it three days later in an interview with a state investigator, and pointed out that Damond’s fingerprints had not been found on the squad car.

“There is no conclusive proof she ever touched that car,” Sweasy said.

She also sought to knock down Noor’s testimony that he had seen fear in Harrity’s eyes as Damond appeared at the window, that Harrity had said “Oh Jesus!” and that Harrity had been struggling to pull his gun when Noor fired.

“Whatever Harrity said or did, it was not a command for the defendant to shoot and kill Ms Ruszczyk,” Sweasy said.

After the closing arguments, Judge Kathryn Quaintance dismissed alternate jurors, leaving a jury of 10 men and two women. Half the jurors, including both women, are people of colour.

The death of Damond, 40, a life coach who was engaged to be married a month after the shooting, sparked outrage in both the US and Australia, cost Minneapolis’ police chief her job and contributed to the electoral defeat of the city’s mayor a few months later.

Noor, 33, is a Somali American who became a police officer with a mid-career switch from jobs in the business world. He broke more than a year and a half of silence about the shooting when he testified in his defence last week, saying had had became a police officer because he “wanted to serve”.

His hiring two years before the shooting was celebrated by Minneapolis leaders as a sign of a diversifying police force in a city with a large population of Somali immigrants.

Neither officer had a body camera running when Damond was shot, something Harrity blamed on what he called a vague policy that didn’t require it. The department toughened the policy after Damond’s death to require that the cameras be turned on when responding to calls.