Australia has demanded explanation from the United States on the fatal shooting of an Australian national by a police officer in the American city of Minneapolis over the weekend.

The woman, 40-year-old Justine Damond, was killed near her home by a single gunshot wound fired through an open window of a police car shortly after she called police to report a possible assault on Saturday night.

Speaking on Wednesday morning, Prime Minister Malcolm Turnbull said he sought answers from the US. So did the Australian consul-general in Chicago, Turnbull said.

The Australian prime minister also called the shooting “shocking” and “inexplicable.”

Damond (pictured below) had been living in the US since three years earlier and was due to marry in August.

Australian Prime Minister Malcolm Turnbull (photo by AFP)

“How can a woman out in the street in her pyjamas seeking assistance from the police be shot like that?” Turnbull asked in his Wednesday remarks.

US police confirmed the details of her death three days later, on Tuesday, as well as the identities of the two police officers involved in the shooting, but did not explain why the shooting took place.

The officers, Mohamed Noor and Matthew Harrity, have been placed on administrative leave.

Noor (pictured below) was the officer who shot the woman, and he was in the passenger seat as they drove near her house looking for a suspect. Their body cameras and vehicle dashboard camera had been turned off during the shooting. Police said the cameras should have been turned on.

US investigators said the officers were startled by a loud sound prior to the shooting, according to the Minnesota Bureau of Criminal Apprehension (BCA), which did not explain what the source of the sound was.

Officer Harrity told investigators on Tuesday that he had been “startled by a loud sound” near the squad car just before Damond approached. According to an unidentified officer, the sound may have been caused by fireworks that sounded like gun shots.

Don Damond, the victim’s fiancé, said her family and he had been “provided with almost no additional information from law enforcement regarding what happened after police arrived.”

Minneapolis Mayor Betsy Hodges said she, too, had been in the dark about the fatal shooting.

“I have the same questions everyone else does,” Hodges said. “Why weren’t the body cameras on? What happened in the shooting? Those are burning questions we all want the answers to.”

Noor, who had just two years’ experience on the force, had earlier been sued for having violated a woman’s rights when, along with two other officers, he forced their way into her house and took her to a mental hospital despite her will.

The relatives and friends of Justine Damond hold a vigil at Sydney’s Freshwater Beach in Australia, July 19, 2017. (Photo by Reuters)

Keith Ellison, a Democratic member of the US Congress, whose district includes Minneapolis, said authorities “need to confront the reality of so many unarmed people killed by the same officers who swear an oath to protect us.”

“Justine’s death shows no one should assume ‘officer-involved shootings’ only happen in a certain part of town or to certain kinds of people,” she added.

The police shooting of unarmed people is not a rare incident in the United States. According to The Washington Post’s database, police shoot and kill almost 1,000 people a year.

Meanwhile, Damond’s family held a vigil for her in Sydney’s Freshwater Beach on Wednesday morning. At least 300 people gathered at the beach, where they lit candles in silence and released flowers into the ocean.