A mystery man on a bicycle could hold the key to the fatal US police shooting of Australian spiritual adviser Justine Damond.
The Minnesota Department of Public Safety Bureau of Criminal Apprehension said today that the two officers at the scene, including Officer Mohamed Noor who fired the fatal bullet, saw a white male aged between 18 and 25-years-old on a bicycle immediately before the shooting.
Noor's partner, Officer Matthew Harrity, told BCA investigators about the cyclist.
The individual stopped at the scene and watched as the officers provided medical assistance to Damond after Noor shot her, the BCA said.
"I would implore the person to come forward," Minneapolis Mayor Betsy Hodges told a press conference.
Damond, who was raised in Sydney, died in her pyjamas on Saturday night local time after calling Minneapolis police for help, fearing a sexual assault was happening in an alley behind her Fulton home.
Harrity also provided fresh insight into why Noor may have suddenly shot Damond. The BCA investigators said Harrity told them as he drove the police vehicle down an alley behind Damond's home "he was startled by a loud sound near the squad" car.
He said Damond approached the driver's side window of the car immediately after the sound.
Harrity said Noor then discharged the weapon, striking Damond through the open driver's side window. Damond died at the scene from the gunshot to her stomach.
Noor has declined to be interviewed by BCA agents, and his lawyer has not provided clarification on when, if ever, an interview would be possible.
"We cannot compel Officer Noor to make a statement ... but I wish that he would," Hodges said.
Damond, 40, was set to marry her American fiance, Don Damond, next month.
Damond, Damond's family, Australian Prime Minister Malcolm Turnbull and the Minneapolis community have all raised concerns about the lack of information released after the killing.
A police radio recording from the incident includes a reference by one unnamed officer that fireworks may have been set off at the time of the shooting.
The BCA said crime scene personnel recovered a cellphone near Damond. She was not carrying a weapon.
Investigators also confirmed police body cameras were not turned on until after the shooting incident. The squad car camera was not turned on. Investigators said they are aware of no video or audio of the shooting.