An Australian woman was dressed in her pyjamas when American police gunned her down, harrowing new details surrounding her death have revealed.

Justine Damond, who also uses the name Justine Ruszczyk, was at home on Saturday night when she called 911 to report a noise and a possible assault in an alley in South Minneapolis, Minnesota.

While police did not have body cameras switched on during the shooting, sources with knowledge of the incident claim the officers arrived at the alley at 11.30pm on Saturday night.

Ms Damond reportedly walked up to the car and began talking to the driver when an officer in the passenger seat pulled a gun and shot her through the drivers side door. No weapon was discovered at the scene, the Star Tribune reports.

The 40-year-old was originally from Sydney but had been living in the US for three years and was due to marry American businessman Don Damond, 50, in August.

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Justine Damond (pictured) was shot dead in her pyjamas by police in the United States, after calling 911 to report a disturbance in an alley near her home at South Minneapolis, Minnesota

Her partner and soon-to-be stepson were not at home when the 40-year-old was shot by police on Saturday night

Ms Ruszczyk was originally from Sydney but had been living in the US for three years and was engaged to marry American businessman Don Damond (right), 50, in August

Shattered friends said the woman and her fiance were due to marry in August, with Ms Damond already using her husband's surname on her website.

At the time of the shooting Mr Damond, the vice president of Little Six Casino was away on business.

Her soon-to-be stepson Zach was reportedly also not at the home on Saturday night, returning on Sunday to discover the crime scene.

And just hours after the shooting he spoke to a local activist group, slamming police over the death of Ms Damond - who he called his 'best friend'.

'Basically my mum's dead because a police officer shot her for reasons I don't know,' Zach Damond said.

'I demand answers. If anybody can help, just call police and demand answers. I'm so done with all this violence. It's so much bulls**t. America sucks.

'She was a very passionate woman, she thought something bad was happening - and next thing you know they take my best friend's life.'

Ms Damond's Australian-based family released a statement through the Department of Foreign Affairs and Trade on Monday afternoon.

Ms Damond was shot in an alleyway on 51st Street in the Fulton neighbourhood (pictured)

Ms Damond was with her soon-to-be stepson when she called police to report a noise in an alley near her home in South Minneapolis, Minnesota, on Saturday

When police arrived at her home at around 11.30pm, 'one officer fired their weapon, fatally striking the woman' as she reportedly stood in her driveway

Just hours after the shooting Zach Damond (pictured), her heartbroken soon-to-be stepson, spoke with close friends of the woman and slammed police over her death

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

'We will not make any further comment or statement and ask that you respect our privacy.'

Ms Damond attended Manly High School and the University of Sydney.

Her friend Matt Omo, an Australian, told the ABC he hoped something positive could come from the tragedy.

'I only hope this evolves into something that can make a positive impact for the world,' he said.

In a statement, the Bureau of Criminal Apprehension said an investigation was in its early stages, but that police did not have their body cameras on during the incident.

Both officers involved in the shooting have been forced to take paid administrative leave, as is standard procedure following similar incidents.

Less than a week earlier it was revealed that officers across the city were using body cameras at what appeared to be a low amounts, despite their high-profile roll out.

Under Minneapolis Police Department policy, officers 'should manually activate their PVR (portable video recorder) to Record Mode when reasonably safe and practical' in situations including 'suspicious person stops' and 'crimes in progress'.

Friends of the woman told the Star Tribune that she had often spoken out against gun violence and told 'how much better' things were in Australia.

A timeline shows the events that led up to the fatal shooting

Ms Damond (pictured) was a 'corporate speaker, trainer and coach' who worked to spiritually help others and regularly ran workshops, according to her website and social media accounts

At a vigil for Ms Damond, women's activists wrote the names of other people gunned down by police in chalk on the pavement

Ms Damond's friends told US media she had often spoken out against gun violence and told them 'how much better' things were in Australia

WHY DID POLICE HAVE THEIR BODY CAMERAS TURNED OFF? - The use of body cameras, or portable video recorders (PVR), was initiated in Minneapolis during 2016. - Police introduced the technology in an effort to reduce complaints about the behaviour of officers and also to ensure vital video evidence was captured. - In Minneapolis, where Ms Ruszczyk died, the cameras must be manually switched on by police. They are automatic in other parts of the US. - According to Minneapolis government's policy, the body cameras must be turned on by when they anticipate they may be involved in a certain situation. - Situations where they must be switched on include: Traffic stops, arrests, physical confrontations, crimes in progress and suspicious person stops. - It was last week revealed that the usage of body cameras among officers in Minneapolis was low as 4% in some areas when responding to 911 calls. Source: Minneapolis Government Advertisement

Ms Damond's stepson shared images from the vigil, writing: 'people really showed love, thank you'

Ms Damond was a 'corporate speaker, trainer and coach' who worked to spiritually help others, according to her website and social media accounts.

Family friend Julia Reed addressed media on Monday, and said the woman would be 'undoubtedly' very missed.

'She was treasured and loved - we will miss her dreadfully,' she said.

Ms Reed, who had known Ms Damond for 32 years, said she would miss: '[Justine's] energy, intelligence, and the joy she brought to my life'.

Friend Marcus Ritchie mourned 'one of the world's most caring and sensitive souls', and called her 'a true inspiration to us all' in a Facebook post.

'There is no way to justify this incident as Justine Ruszczyk was such a beautiful person,' he wrote.

'There will be a lot to answer for!'

Originally trained as a vet at the University of Sydney, she was 'supporting individuals and organizations to discover the power and potential within their own brains and hearts.'

Ms Damond regularly held sessions at the Lake Harriet Spritual Centre, with many of her talks recorded and uploaded to YouTube.

She grew up on Sydney's northern beaches, with her father John the owner of a Dymocks bookstore at Warringah Mall and a prominent member of the community.

Hundreds of people gathered outside the Damond residence in the hours after her death to hold a vigil for the woman (pictured)

One mourner drew a heart with 'Justine' written inside, and a red and a yellow rose was laid on either side

Hundreds gathered outside the Damond home in the hours after her death to hold a vigil for the woman, with her neighbours remembering a 'beautiful light'.

'This woman was a beautiful light, she was a healer, she was loved, she should be alive - she should still be here,' one friend said.

Pictures showed a large group of people holding hands in a drive way, with colourful chalk drawings on the pavement - including a heart with 'Justine' written inside, and a red and a yellow rose laid on either side.

Her stepson Zach shared images from the event in his Instagram story, writing: 'people really showed love, thank you'.

One image showed a sign which read: 'Why did you shoot and kill our neighbour and friend?'.

The placard was surrounded by flowers, candles and a letter.

Nearby, a tea towel with an image of Australia was hung on a brick wall.

In a statement, the Minneapolis Bureau of Criminal Apprehension said an investigation was in its early stages, but confirmed police did not have their body cameras on during the incident

Minneapolis Mayor Betsy Hodges said she was disturbed by the shooting and called on BCA to release information about Ms Damond's death as quickly as possible

Minneapolis Mayor Betsy Hodges (pictured) said she was 'heartsick and disturbed by what occurred'

Minneapolis Mayor Betsy Hodges said she was disturbed by the shooting and called on BCA to release information about Ms Ruszczyk's death as quickly as possible.

'As mayor of our city, a wife, and a grandmother, I am heartsick and deeply disturbed by what occurred last night,' Mayor Hodges said, the Star Tribune reports.

'I am heartsick and deeply disturbed by what occurred last night' - Mayor Betsy Hodges

'There are still many questions about what took place, and while the investigation is still in its early stages, I am asking the BCA to release as much information, as quickly as they are able to.

'My thoughts are now with everyone affected by this tragic incident, especially the deceased woman and her family.'