A man accused of beating and strangling his brother-in-law’s family to death in their north-west Sydney home allegedly disclosed his motive for the crime and the method by which he disposed of the murder weapon to a prison inmate months later, a court has heard.
Lian Bin "Robert" Xie is accused of murdering Min "Norman" Lin, 45; Mr Lin’s wife, Yun "Lily" Li Lin, 44; their sons Henry, 12, and Terry, 9; and Ms Lin's sister, Yun Bin "Irene" Yin, 39, in the early hours of July 18, 2009 in Boundary Road, Epping.
He has pleaded not guilty to all charges.
The opening of Mr Xie’s murder trial on Friday heard that the Lin family were killed by a combination of blunt force trauma inflicted by a “hammer-like object” and asphyxiation carried out with a ligature or bar.
The youngest victim, Terry Lin, 9, survived for one to two hours after a "furious struggle" with his attacker, and his 12-year-old brother was alive for at least 30 minutes after the attack.
Min and Lily Lin suffered multiple injuries to the face and head which went far beyond what was required to take their lives.
One member of the Lin family was not present at the time of the attack.
"The Crown case is the assailant was motivated by a bitterness towards at least the adults of the family in the commission of the murders,” Crown Prosecutor Mark Tedeschi told the NSW Supreme Court.
"This was a pre-planned and deliberately executed crime of bitterness".
Mr Tedeschi said that some months after the murders, Mr Xie allegedly shared his motive for the killings.
"The accused told a prisoner in Long Bay Jail a long time after the killings some information the Crown points to as identifying his motive,” he said.
“It relates to a 'loss of face', which has a particular connotation in Chinese culture."
The Crown case is that bloodied footprints at the crime scene on Boundary Road, North Epping, point to Mr Xie as the perpetrator of the crimes.
An analysis of these prints allegedly showed that the killer moved efficiently from one room to another, deliberately killing the adults first because they represented the greatest threat of “resistance or detection”.
The prints also allegedly matched a particular type of Asics running shoe that Mr Xie allegedly favoured.
The court heard that when Mr Xie subsequently learned from his wife that police were interested in this aspect of the evidence, police secretly recorded him cutting up his Asics shoe boxes and flushing them down the toilet.
The jury also heard that, the morning after the murders, Mr Xie tried to stop his wife from walking into main bedroom of the Lin’s home because he knew, without looking, what she would see.
He then allegedly left the house before police arrived, leaving his wife to wait there alone, despite her pleas for him to stay.
It is alleged that Mr Xie subsequently told the prison inmate that he did this because he believed “whoever is the first person found at the scene when a murder is discovered is the prime suspect”.
He also allegedly told the inmate that he disposed of the murder weapon after driving away from the scene.
The court heard that when Mr Xie cleaned his garage the morning of the murder - in a bid to hide any traces of what he had done - he “failed to notice” a small blood smear on the concrete floor.
This smear allegedly contained between “three and five” different blood profiles. Subsequent DNA testing of these blood profiles will be crucial evidence in the case.
The trial continues.