Chinese-born ear, nose and throat specialist Robert Xie repeatedly clubbed two children and three adults around the head and face as they lay sleeping in their home in 2009, hitting one of them 18 times.
The 58-year-old, who emigrated from China 15 years ago, was told he will die in jail for the murders of brother-in-law Norman Lin and his family.
Justice Elizabeth Fullerton told a Sydney court Xie's horrific slaying of the five -- including one as young as nine -- showed "resolve... To persist with the infliction of extreme violence".
"There was a discernable pattern in the shape and contour of many of the blunt force injuries on the heads and faces of the victims."
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Prosecutors said Xie, who had a key to the family home, was motivated by bitterness linked to his lowly standing with the family.
Xie and his wife Kathy Lin -- Norman's sister -- alerted the police to the bodies, leading to a huge investigation spanning Australia and China.
Xie, who was given five life sentences without the possibility of parole, maintains his innocence, and is supported by his wife.
"He is a loving and caring family man," Kathy Lin told reporters outside court.
"He was wrongly charged with a crime he did not commit. He is a scapegoat".
"We need people to support us to correct this miscarriage of justice... To bring him home," she said, adding that Xie will appeal.