Authorities and activists have questioned why Minneapolis police who fatally shot an Australian woman over the weekend did not have their body cameras turned on during the incident.
Justine Damond's American fiancé is also looking for answers about how she was shot.
She had called the police to report a suspected sexual assault near her home, her fiancé Don Damond told reporters outside the home.
"We lost the dearest of people and we are desperate for information," Mr Damond said.
"Piecing together Justine's last moments before the homicide would be a small comfort as we grieve this tragedy."
Also known as Justine Ruszczyk, she had already taken Mr Damond's last name.
Minneapolis Mayor Betsy Hodges and the American Civil Liberties Union (ACLU) of Minnesota called for answers on why the two responding officers failed to turn on their body cameras when they arrived at Ms Damond's home in a quiet, upper-middle-class neighbourhood shortly before midnight on Saturday.
Police shot Ms Damond, originally from Sydney, through the door of their patrol car as she approached them in an alley near her home, the Minneapolis Star-Tribune reported, citing three unnamed sources.
In a statement, Minneapolis Police Chief Janee Harteau called Ms Damond's death "tragic" and promised a "transparent" investigation.
Ms Damond's father, John Ruszczyk, told reporters in Sydney that her death was "our worst nightmare".
"Justine was a beacon to all of us. We only ask that the light of justice shine down on the circumstances of her death," he said.
The officer who shot Ms Damond was identified by the Minneapolis Star Tribune and other local media as Mohamed Noor.
Officer Noor's lawyer, Tom Plunkett, said in a statement that the police officer extends his condolences to Ms Damond's family.
The statement did not describe Officer Noor's role in the shooting, and authorities have not confirmed the identities of the officers involved.
Hundreds took to the streets of Minneapolis on Sunday to protest the shooting.
The state Bureau of Criminal Apprehension (BCA), which reviews shootings involving the police in Minneapolis, said the dashboard camera in the officers' patrol car did not capture the shooting.
The BCA is seeking any civilian video of the incident.
The ACLU of Minnesota called for the release of the audio from Ms Damond's 911 call, along with any audio from the officers' dash camera.
The group's interim executive director, Teresa Nelson, said the officers failed to obey department rules by not having their body cameras on.
Both officers in the incident have been placed on administrative leave, the state BCA said.
