Los Angeles: The former US police officer who shot dead Australian life coach Justine Ruszczyk Damond in an alley behind her Minneapolis home claims his murder conviction "debased the criminal justice system".

Former Minneapolis police officer Mohamed Noor reads a statement before being sentenced in June. Credit:AAP

Mohamed Noor, who is serving a 12.5 year prison sentence after a Minneapolis jury found him guilty a year ago of third-degree murder and second-degree manslaughter, filed an appeal on Friday.

The 34-year-old is requesting a new trial.

"Noor's prosecution was a sordid series of events that debased the criminal justice system," Noor's legal team wrote in a 69-page appellant's brief filed in the Minnesota Court of Appeals.