Justine Damond's distressed 911 calls have been released, revealing exactly why she rang.

Transcripts of the two 911 calls Australian woman Justine Damond made to police before she was shot and killed on Saturday night have been released.

The transcripts, released Wednesday afternoon US time, reveal Damond called police after she became concerned that a sexual assault was occurring at her neighbour’s home.

Transcripts obtained by the Star Tribune show Justine called police at 11.27 pm on Saturday night.

EXCLUSIVE: 911 call transcript: Before being shot by officer, Justine Damond called in possible rape https://t.co/FAdJfNkQJr pic.twitter.com/6mwhubwwNd

— Star Tribune (@StarTribune) July 19, 2017

“Hi, I’m, I can hear someone out the back and I’m not sure if she’s having sex or being raped,” she told the operator.

“I think she just yelled out ‘help’ but it’s difficult. The sound has been going on for a while, but I think, I don’t think she’s enjoying it.”

Damond then continued to try to describe what she was hearing.

“It sounds like sex noises, but it’s been going on for a while and I think she tried to say ‘help’ and it sounds distressed,” she said.

The operator told her that officers were on their way to her address.

Eight minutes later, at 11.35 pm, Damond called 911 again to ensure police were still coming to the scene. She confirmed her address and told the operator the woman in question was still screaming.

Just minutes later, the 40-year-old Australia-born woman, who was set to marry her fiancé next month, was shot and killed by one of the responding officers.

It’s believed Officer Mohamed Noor, 31, shot across his partner, Officer Matthew Harrity, 26, through the open driver’s side window, hitting Damond in the abdomen.

The family of Justine Ruszczyk Damond is considering filing a lawsuit against the city of Minneapolis. #sun7 pic.twitter.com/1qb8ZUKlE6

— Sunrise (@sunriseon7) July 20, 2017

The officers performed CPR on Damond for four minutes until paramedics arrived but she died at the scene.

Hours before the transcripts were released, Noor’s family, spoke to reporters.

News Corp reports the family professed Noor’s innocence, telling reporters the incident was “unfortunate”.

“We feel so bad about this, we are traumatised ourselves,” a family member said. “It’s so unfortunate.

“If you wait for the investigation, you’ll know it was an honest and sincere event that transpired. Until then we can’t really say anything.”

Yesterday, a source close to Minneapolis law enforcement told AAP that Noor may have been startled by the sound of fireworks before he fatally shot the bride-to-be.

The reference to fireworks is heard during the police radio conversations between Noor, his partner, the police dispatcher coordinating the emergency call and other officers rushing to scene.

At one point the dispatcher asks for a precinct sergeant to acknowledge a report of "two shots heard from the east."

"We heard those sounds from the station," an officer responds.

"Those are probably aerial fireworks."

Another report from 5 Eyewitness News suggests the officers believed they were "caught in ambush" after they heard someone "pounding loudly on their SUV."

A source told the news outlet that the two officers were watching a bicyclist cross the passenger side of their vehicle when they were alarmed by a pounding noise on the driver's side of their patrol car.

Noor and Harrity have been placed on paid administrative leave after the incident. Noor has so far refused to be interviewed formally in relation to Damond's death.

Under federal law, Noor cannot be compelled to speak to investigators. His attorney has not yet provided any clarification to the Minnesota Department of Public Safety Bureau of Criminal Apprehension on when, if ever, an interview will be possible.

Damond, who grew up on Sydney's Northern Beaches in Australia before moving to the US, was due to marry her fiancé, Don Damond, in weeks.

Friends close to the 40-year-old woman have described her death as "senseless."

"This is a massive loss," a friend from Sydney told Mamamia yesterday. "She touched the lives of so many people, but she did more than that as well.

"She actually really helped people, too. She really changed our lives."