Justine Damond was shot dead by police in Minneapolis. Photograph: LinkedIn/AAP
The woman has been named as Justine Damond, who ran meditation workshops at the Lake Harriet Spiritual Community.
Her stepson, Zac Damond, said she had called police after hearing a noise near her house.
Two Minneapolis police officers responded to a 911 call of a possible assault just north of the 5100 block of Washburn Avenue S just before 11.30pm Saturday, the state Bureau of Criminal Apprehension said in a statement,
according to the Star Tribune. At one point, an officer fired their weapon, fatally striking a woman.
The BCAs investigation is in its early stages. More information will be available once initial interviews with incident participants and any witnesses are complete The officers body cameras were not turned on at the time and the squad camera did not capture the incident. Investigators are attempting to determine whether any video of the incident exists.
The two officers involved are on paid administrative leave.
Her stepson said Damond, an Australian in her 40s, was passionate and his best friend.
Basically my mum was shot for reasons I dont know, he said in a video posted on Facebook on Monday morning.
I just know she heard a sound in the alley so then she called the police and the cops showed up and she was a very passionate woman, she probably thought something bad was happening and then next thing I know they take my best friends life.
The mayor of Minneapolis, Betsy Hodges, said she intended to find out why the officers body cameras were not turned on.
As mayor of our city, a wife, and a grandmother, I am heartsick and deeply disturbed by what occurred last night, she posted on Facebook.
Damond is believed to have been living in the US for at least the past three years. Her personal website says she trained as a veterinarian and practised yoga and meditation for 17 years.
The Australian Department of Foreign Affairs and Trade says it is providing consular support to the family of an Australian woman killed in the US.