The mental state of Minneapolis police officer Mohamed Noor when he shot dead Australian yoga instructor Justine Damond has emerged as potential keys to the upcoming murder trial

New court filings by prosecutors also revealed Noor, who has refused to speak publicly about the shooting, gave what appears to be "his first version of the facts since the incident occurred 17 months ago to a defence investigator".

Noor was fired from the Minneapolis Police Department last March after he was charged with the second and third-degree murder of Ms Damond

.He faces up to 40 years' jail if convicted at the April 1 trial in Minneapolis.