An Oakville man has pleaded guilty to murdering decorated NSW police officer Bryson Anderson on what was to be the first day of his Supreme Court trial.
The man's mother has pleaded guilty to manslaughter over the crime, and this has been accepted by prosecutors.
Mitchell Barbieri, 21, and his mother Fiona Barbieri, 47, admitted to their crimes on Wednesday in a courtroom packed with the officer's family and his former police colleagues.
Mitchell Barbieri now faces life in jail, as a life sentence is mandatory in cases where a police officer is murdered in the course of his or her duty.
Both mother and son had originally been charged with murder over the crime.
But the court heard on Wednesday that the Crown accepted the plea of manslaughter for Fiona Barbieri on the grounds that she had been suffering "a substantial impairment brought about by an abnormality of mind".
Inspector Anderson was murdered on December 6, 2012, at the Barbieris' Oakville home after police received an urgent call from neighbours to attend the property.
Officers allegedly found the Barbieris barricaded inside their brick bungalow and firing arrows at officers.
It is alleged that, when Inspector Anderson went to the back entrance of the house to negotiate with the pair, he was attacked with a knife by Mr Barbieri, while his mother swung a block hammer at other officers who tried to intervene.
The pair will return to court for sentencing next week.
