Robert Xie will die in jail after three judges upheld his murder convictions for bludgeoning five relatives to death in their Sydney home.
The 57-year-old, who faced four trials before being found guilty by a jury in 2017, challenged the convictions on eight grounds.
But the NSW Court of Criminal Appeal on Monday dismissed his challenge, finding the former ear, nose and throat specialist was not the victim of a miscarriage of justice.
Chief Justice Tom Bathurst, sitting with Justices Robert Allan Hulme and Robert Beech-Jones, read a summary of their decision, watched by Xie via an audiovisual link from jail.
When his case was dismissed, he covered his face with his hands while his wife Kathy, who has also always maintained his innocence, showed no outward reaction as she sat in the courtroom.
Justice Elizabeth Fullerton had imposed five life sentences on him, describing the killings as "heinous in the extreme".
Xie's newsagent brother-in-law Min Lin, 45, his wife Lily Lin, 43, the couple's sons Henry, 12, and nine-year-old Terry, and Lily's 39-year-old sister, Irene, suffered horrific head injuries after being attacked in their bedrooms in the early hours of July 18, 2009.
Their 15-year-old daughter Brenda, who also was in court for the appeal decision, was on an overseas school excursion at the time and went to live with her uncle and aunt after the murders, before his arrest
Justice Fullerton found Xie entered the Lin house, only 300 metres from his own home, with a key cut from a spare one entrusted to his wife.
He also used his family knowledge about the layout of the bedrooms upstairs and the location of the outside power box to enable him to turn off the electricity and "enter the house by stealth".
Xie's appeal grounds included claims about evidence by scientist Dr Mark Perlin concerning the likely contributors to a stain, containing DNA from multiple persons, found in his garage 10 months after the killings.
Dr Perlin used a computer-based probabilistic analysis to determine the likely contributors to "Stain 91", with the Crown contending it contained DNA from at least four of the dead relatives.
In rejecting the complaints, the three judges noted some of the issues were not raised at trial and others had no merit.
Xie's lawyers also argued the judge erred in admitting "coincidence evidence" asserting similarities between a piece of blood-soaked cloth found in one of the bedrooms and a folded towel on a homemade massage device found at Xie's home in May 2010.
The murder weapon was never found, but the prosecution submitted it was a hammer-like implement and that the blood-soaked piece of cloth was at one time secured to the head of the massage device.
The appeal court ruled that the evidence of finding the device had "significant probative value" and was correctly admitted into the evidence.
It also rejected a contention that Xie suffered a miscarriage of justice due to directions given by the judge about his alibi defence, noting the issue was not brought up at the trial.
He told police that at the time of the killings he was in bed asleep with his wife.
Justice Fullerton had found it was "very likely" Xie had sedated his wife and said it was possible she just didn't wake up when he left their house sometime after 2am.
The Crown had submitted Xie was partly motivated by resentment and humiliation at his perceived "inferior" status in the extended family.
Xie did not appeal his sentence.