A distraught stepson demands for answer after his Australian mother was shot by police in Minneapolis
Justine Damond, 40, was killed in what police confirmed was an "officer-involved shooting" in the city's Fulton neighbourhood.
Minnesota newspaper The Star Tribune reports Ms Damond was dressed in her pyjamas when she went to the driver's side door of the police vehicle that responded to the emergency call.
She was talking to the driver when the officer in the passenger seat pulled out his gun and shot across his fellow officer.
The Sydney woman had been living with her fiance and son in Minneapolis.
In a video shared online, Ms Damond's stepson Zach Damond, 22, recounted what had happened on Saturday night before his stepmother called the police.
"I just know that she heard a sound in the alley, so she called the police, and the cops showed up," he said.
"She was a very passionate woman, she probably, she thought something bad was happening, and next thing I know they take my best friend's life."
In the emotional video, Mr Damond went on to condemn police and demand answers over what happened.
"Basically my mum's dead because a police officer shot her for reasons I don't know," he said.
"I demand answers. If anybody can help, just call police and demand answers. I'm so done with all this violence.
"America sucks, these cops need to get trained differently ... I'm just done, f*** the police. I'm just done. This has to stop."
Minneapolis police confirmed the incident in a statement.
"Two Minneapolis police officers responded to a 911 call of a possible assault just north of the 5100 block of Washburn Avenue South just before 11.30pm Saturday," it read.
"At one point an officer fired their weapon, fatally striking a woman."
The officer who shot the woman was under investigation by the Minnesota Bureau of Criminal Apprehension, which was interviewing witnesses and "incident participants".
Minnesota police wear body cameras, but the officers involved did not have their cameras turned on at the time.
Police said a squad camera also failed to capture the incident, and investigators were seeking to determine if any video of the incident existed.
Ms Damond, who also went by the name Justine Ruszczyk, was engaged and set to be married next month.
Ms Damond trained as a veterinarian in Sydney, and went on to study and practice yoga and meditation. She was a qualified yoga instructor, and a personal health and yoga coach.
Friends have begun to pay tribute to on social media.
She has been described as an "incredible woman" and a "brilliant, well-known, local healer".
"My heart aches for her fiance and mother in law who often accompanied Justine while she taught some profound meditation classes, sound healing classes, and her Sunday messages at Lake Harriet Spiritual Community," Angela Pederson wrote on Facebook.
"I am happy to have known Justine and her untimely, tragic death is a reminder to live life fully, love deeply, and take risks to love as we are not promised tomorrow."
At the scene where Ms Damond was shot, locals have gathered for a vigil and left behind messages of support drawn in chalk on the footpath.
Minneapolis Mayor Betsy Hodges said she was "heartsick and deeply disturbed" by the shooting.
"As Mayor of our City, a wife, and a grandmother, I am heartsick and deeply disturbed by what occurred last night," she wrote on Facebook.
"My thoughts are now with everyone affected by this tragic incident, especially the deceased woman and her family."
The Australian Department of Foreign Affairs and Trade confirmed to news.com.au it was "providing consular assistance to the family of an Australian woman who died in a shooting in Minneapolis".