Details of the shocking sexual motive behind the Lin family massacre can now be revealed after the only surviving family member broke an eight-year silence.
Five members of Brenda Lin's family were brutally killed by her uncle Robert Xie in July, 2009, when he let himself into their North Epping home and bashed them to death with a hammer-like object as they slept.
Xie, 53, was this week sentenced to five life sentences and will never be released from jail.
Details of the motive behind the murders - along with Ms Lin's identity - have not been able to be reported until now. She has given her consent to be identified by participating in an interview with the Seven Network's Sunday Night program.
After three years of hearings, and four Supreme Court trials, Xie was found guilty of the killings in January of murdering his brother-in-law Norman Min Lin, 45; Mr Lin's wife Yun Li Lily Lin, 43; her sister Irene Yin Yun Bin, 39; and the Lins' two young boys Henry, 12, and Terry, 9, in their North Epping home in July 2009.
The massacre was one of the most brutal in Australian history.
Ms Lin, the eldest child of Min and Lily Lin, told the NSW Supreme Court trial Xie sexually assaulted her on a number of occasions when she moved in with his family after the murders. She also gave evidence of instances of inappropriate touching before the killings.
One of the motives advanced by the Crown was that Xie would be able to continue to offend against Ms Lin with her family gone and with her living under his roof.
"He was someone that I trusted...As a person who isn't a murderer. And also know what he has done," Ms Lin said in a Sunday Night promotion.
"I'd give anything to have my family back."
Ms Lin spoke of her harrowing ordeal in her victim impact statement read to her uncle's sentencing hearing. She was on a trip to New Caledonia when the murders occurred.
"I do not even know how to begin to express how the murder of my immediate family have impacted my life - there are not enough words to describe the pain and suffering caused me and those around me."
She never hugged her father goodbye during the last meeting, something which was now her "biggest regret".
"The pain of losing loved ones, that never goes away and does not get any easier with time. As time goes on others may forget but I will have to live with the aftermath of the crime for the rest of my life."
In her sentencing remarks, Justice Fullerton elaborated on the motives.
"At the trial of the offender the Crown relied upon two possible motives operating separately or in combination in proof of the Crown case. First, the offender's sexual interest in [Ms Lin], as evidenced by his sexual interest in her before the murders and his serialised sexual abuse of her after the murders when, upon the death of all members of her immediate family, she became a member of his household."
The second motive was Xie's perception that he did not have equal status within the family - and his jealousy of how highly regarded Min Lin was.
At Monday's sentencing, Justice Elizabeth Fullerton read extracts from Ms Lin's emotional victim impact statement where she told of her life becoming "hollow" and "bittersweet".
"She described missing the support and guidance her parents had given her as their eldest child with the certain knowledge that would have continued," Justice Fullerton said.
Ms Lin had trouble sleeping, struggled with her studies and was dealing with many "mental health issues".
Her victim impact statement told of being welcomed into other "loving families" it would never be the same as having her own family's "love and support".
"[She] told me her achievements feel hollow and as she has passed various milestones from adolescence to early adulthood since the death of her family, celebrating those achievements with others is bittersweet," Justice Fullerton said.
Ms Lin was present in court at the sentencing, sitting just metres away from her uncle as the judgment was delivered.
Justice Fullerton said: "I acknowledge the profound grief she has suffered and continues to suffer. I also commend her for her strength and dignity, and her courage as she faces the future without parents, siblings or a loving aunt."
The impact the murder spree had on Ms Lin was a factor in the decision to impose life sentences on Xie.
"While the law does not permit a sentencing judge to take into account in the imposition of sentence any additional penalty because a family member of a murder victim has suffered through their death... in this case the far reaching and immeasurable harm done to [Ms Lin] is also an aspect of the harm done to the community and, for that reason... I also take that into account when imposing life sentences in this case."
Xie's sentencing heard about the bloody mess found inside the tidy, two-storey family home.
The amount of blood in the bedrooms was not only an "immediate and graphic" illustration of the "murderous assault" which killed them, it also revealed they were killed in the rooms - and in the case of the adults - in their "blood soaked" beds.
Blood was smeared up the walls and across the floor.
Of all five victims, young Terry Lin was the only one not killed instantly, such was the severity of the injuries each family member received to their heads and faces.
A distinct pattern was visible on their battered faces, with a forensic pathologist later determining a hammer-like object was used as the murder weapon.
Justice Fullerton said the murders were "heinous in the extreme" and were "a single episode of brutal and calculated murderous violence".
She was satisfied Xie killed the family with a hammer like object with a rope attached "most likely so he didn't lose control" of it and also to maximise "the degree of force to ensure he killed with speed and efficiency".
She believed Xie used a key that was cut for his wife Kathy - Min Lin's sister - and used his knowledge of the home he gained as a "trusted family member" to carry out the murders.
Xie showed no emotion when the sentence was passed and he learned he would spend the rest of his life in jail.
Outside court his wife Kathy Lin - Min Lin's sister - vowed they would fight on.
"Robert's innocent. He did not kill my brother's family. He is a loving and caring family man," she said.
Kathy's support of Xie is in sharp contrast to her parents, who believe he was the killer.
"Robert has a good relationship with my family. He was wrongly charged with a crime he did not commit - he is a scapegoat in this injustice."
Xie would appeal the conviction.
"He is a good husband, father, son, uncle and friend," she said.