US police officers have shot dead an Australian woman who reportedly called 911 after hearing a noise near her home in Minneapolis.

Minnesota’s public safety department said a woman was shot in Minneapolis after two officers responded to a callout about a possible assault on Saturday at 11.30pm local time. The police officers did not have their body cameras turned on.

The woman has been named as Justine Damond, who ran meditation workshops at the Lake Harriet Spiritual Community. Damond, originally Justine Ruszczyk, used the name of the man she was due to marry in August, Don Damond, the local Star Tribune reported.

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 BCA’s 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, 40-year-old Sydneysider, was “passionate” and his “best friend”.

“Basically my mum was shot for reasons I don’t 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 friend’s life.”

Later on Monday the Australian Department of Foreign Affairs put out a brief statement on behalf of the family.

“This is a very difficult time for our family,” the statement said. “We are trying to come to terms with this tragedy and to understand why this has happened.”

No further comment would be offered, the statement said, asking for privacy for the family.

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.

Nekima Levy-Pounds, a local civil rights attorney and police reform activist who is running for mayor of Minneapolis, expressed solidarity over Damond’s death.

“We stand with the people of Australia in demanding justice for Justine Damond,” Levy-Pounds said. “Her death could have been prevented. Were it not for the increasing militarisation of US police forces, she would still be alive today.”

Levy-Pounds, who was a leading figure in protests against the police killings of unarmed black men Jamar Clarke and Philando Castile, said Damond was the latest casualty of a “flawed system of policing”.

“The tragic and senseless death of Justine Damond at the hands of the Minneapolis Police Department illustrates everything that is wrong with our system of policing in the US,” she said.

“For years, activists and community members have raised concerns about the ‘shoot first, ask questions later’ mentality amongst some police officers. Beyond that, police officers have routinely escaped accountability for perpetuating violence against civilians and have been allowed to kill with impunity. Justine Damond is the latest casualty of a flawed system of policing, that is urgently in need of being overhauled. The fact that her case has been shrouded in a cloak of secrecy merely reinforces concerns surrounding a lack of transparency and accountability within this system.”

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 said it was providing consular support to the family of an Australian woman killed in the US.