The US police officer who shot dead Australian woman Justine Damond in a Minneapolis alley had little more than two years' experience on the force.

Key points: Damond reportedly approached the police car in her pyjamas and was shot through the door

Damond reportedly approached the police car in her pyjamas and was shot through the door Officials are trying to figure out why the police body cameras were not turned on

Officials are trying to figure out why the police body cameras were not turned on Hundreds take to the streets to protest a spate of police shootings

Minneapolis police officer Mohamed Noor has been on the job little more than two years. ( Star Tribune: City of Minneapolis )

Officer Mohamed Noor shot the 40-year-old bride-to-be more than once from the passenger seat of his police vehicle.

Ms Damond called police just before midnight on Saturday after hearing a possible assault taking place in an alley behind her Minneapolis home.

She was in her pyjamas when she approached Noor's police vehicle.

Mr Noor, the first Somali-American officer at Minneapolis' 5th Precinct, was in the passenger seat and fired multiple times across his partner at Ms Damond, Minneapolis TV station KSTP reported.

A mobile phone was reportedly found near Ms Damond's body.

The moments immediately after the shooting were recorded over police radio.

One of the officers told dispatch that shots had been fired and asked for medical assistance.

"Shots fired. Can we get EMS Code 3 to Washburn and 51st Street. We have one down."

A Code 3 is a call for vehicles to respond using their lights and sirens.

The officer told dispatch they were starting CPR on the victim, before adding: "There are no suspects at large".

The officer then asked where their back-up was, to which the dispatcher responded: "EMS is coming, rescue is coming."

The dispatcher confirmed police had heard the sound of shots being fired in the west, and two shots had been heard in the east.

Another officer then said: "We heard those sounds from the station, those were probably aerial fireworks."

Police officer facing two other complaints

Sorry, this video has expired Minneapolis neighbourhood grappling with shooting of Australian woman ( Ben Knight )

Mr Noor was sued earlier this year after a May 25 incident in which he and other officers took a woman to the hospital on a mental health hold.

The lawsuit claims Mr Noor and the other officers violated the woman's rights when they entered her home without her permission and Mr Noor grabbed her wrist and upper arm.

Mr Noor relaxed his grip when the woman said she had a previous shoulder injury, the lawsuit says.

Television station KSTP reported that city records show Mr Noor had three complaints on file.

The station did not provide details on the nature of the complaints but said one was dismissed with no disciplinary action, while the other two were pending.

"Officer Mohamed Noor extends his condolences to the family and anyone else who has been touched by this event," his attorney Tom Plunkett said in a statement.

"He takes their loss seriously and keeps them in his daily thoughts and prayers.

"The current environment for police is difficult, but Officer Noor accepts this as part of his calling.

"We would like to say more, and will in the future.

"At this time, however, there are several investigations ongoing and Officer Noor wants to respect the privacy to the family and asks the same in return during this difficult period."

The shooting has shattered Ms Damond's family and friends in Australia and the US and outraged residents of Minneapolis and adjoining St Paul who are still reeling from other high-profile police shootings.

Ms Damond's American fiance Don Damond thanked family and friends around the world "for the amazing outpouring of love and support".

"Our hearts are broken and we are utterly devastated by the loss of Justine," Mr Damond said.

Justine Damond pictured with her fiance Don and stepson Zach. ( Facebook: Don Miller Damond )

External investigation into shooting 'expedited'

Ms Damond's death from a police gun has also generated widespread media coverage across the US.

Officer Noor and his partner's body cameras were not turned on and their police car dashboard camera did not capture the incident.

It is not clear why the officers' body cameras were not turned on.

The department phased in body cameras for all of its officers over the last year.

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Department policy allows for a range of situations in which officers are supposed to turn cameras on, including "any contact involving criminal activity" and before use of force.

If a body camera is not turned on before use of force, it is supposed to be turned on as soon as it is safe to do so.

Once the investigation is complete, Hennepin County Attorney Mike Freeman will decide whether to charge the officer.

Mr Freeman would not comment on the broader case, but said both officers likely should have turned on their body cameras as they were approached by Ms Damond in an alley.

In a short statement, Minnesota Police Chief Janee Harteau described the death as "tragic".

"I understand why so many people have so many questions at this point," the statement said.

"I have many of the same questions and it is why we immediately asked for an external and independent investigation into the officer-involved shooting death.

"I've asked for the investigation to be expedited to provide transparency and to answer as many questions as quickly as we can".

Ms Damond's death is being investigated by the Minnesota Bureau of Criminal Apprehension, not the Minneapolis Police Department.

Officer Noor and his partner are on paid administrative leave.

A woman cries over the death of Justine Damond. ( The Star Tribune: Elizabeth Flores )

At least 524 people fatally shot by police in US this year

The American Civil Liberties Union said the officers should face penalties for making the truth harder to find.

Minneapolis Mayor Betsy Hodges said she has "a lot of questions why the body cameras were not on".

"I know many of you are frustrated at the pace of information being released around Saturday night's shooting," she wrote in a Monday Facebook post. "I am too."

The Washington Post reported Ms Damond was one of at least 524 people fatally shot by police in the US this year and the fifth in Minnesota.

The Minneapolis-St Paul area is still reeling from the acquittal last month of a police officer who shot dead a man, Philando Castile, during a traffic stop while Castile's girlfriend live streamed the horrifying incident.

Violent protests also flared after two officers fatally shot 24-year-old Jamar Clark in 2015 and were not charged.

A makeshift memorial has been set up for Ms Damond in Minneapolis. ( ABC News: Ben Knight )

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