A jury which convicted Robert Xie of bludgeoning five relatives to death was provided with misleading, confusing and unfairly prejudicial DNA evidence, his appeal has been told.
This included testimony about a stain found on the floor of Xie's garage - 300 metres from the murder scene - 10 months after the killings, his barrister Belinda Rigg SC said.
After four trials, a jury in 2017 found Xie guilty of murdering three adults and two children in the bedrooms of their Sydney home in the early hours of July 18, 2009.
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 when they were attacked with a hammer-like object attached to a rope.
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Xie found guilty of murdering family
The now 56-year-old Xie is behind bars for the rest of his life and appeared via video-link from Lithgow jail at his Court of Criminal Appeal hearing on Monday.
Ms Rigg said she expected the three judges would hear submissions related to the DNA evidence for the next three days, to be followed by evidence from two experts.
She said the expert evidence had been silent at the Supreme Court trial on the timing of when the DNA material in the garage was left there.
At trial, the Crown contended the stain was blood which "most likely" contained DNA of four Lin family victims and which Xie "transferred" immediately after the murders.
But the defence disputed the assertion that the stain was blood and, if it was, claims about the contributors to the DNA.
Ms Rigg said 10 blood relatives, including the five people killed, had resided at or visited Xie's residence.
The hearing continues.
