Fuelled by resentment and humiliation at his "inferior" status in the Lin family, Robert Xie crept into a Sydney house and bludgeoned five relatives to death.
Days later, he and his wife, Kathy Lin, made an emotional public plea for information to help solve the terrible crimes.
They asked that media not show their faces because of concerns for their own safety.
Xie said he couldn't imagine any reason why anyone would want to harm the family, describing his dead brother-in-law as a "very nice, hard-working, friendly person".
But now, more than seven years and four trials later, the 53-year-old is facing life behind bars after a NSW Supreme Court jury on Thursday found him guilty of the five murders.
It took the jury eight days of deliberations after a six month trial.
Xie had pleaded not guilty to murdering the five in their North Epping home.
As the majority verdict was handed down, Xie told the court he did not murder the Lin family.
"I am innocent," he told the jury as he left the court.
The grandmother of the children Xie bludgeoned to death wailed after he was convicted of their murders.
His wife Kathy broke down in tears, while the grandmother of the dead children wailed as she left court following the verdicts.
Feng Qin Zhu and her husband clutched photos of their family outside court calling for harsh punishment for the "evil murderer" after their son-in-law was found guilty of killing their son Min Lin and four other family members.
"My son has been avenged," she said outside court in Mandarin.
"The law has given me the truth."
"God can see this."
Ms Feng held newspaper articles about the case, while she and her husband Yang Fei Lin both held pictures.
"To punish the murderer really harshly in order to get back justice," writing on the picture of the dead boys said, according to a translation.
"To commemorate very kind relatives, to punish harshly the evil murderer," said writing on pictures of the adult victims.
Xie, a former ear, nose and throat specialist, who was arrested in May 2011, faced two aborted trials and a third lasting nine months which resulted in a hung jury.
Xie was found to have left their bed in the early hours of July 18, 2009, hours after attending a "normal" Friday night dinner with his extended family.
His wife confirmed his alibi, that he didn't leave their bed that night, but the Crown suggested Xie sedated her before creeping into the Lin residence around the corner.
Ms Lin lied at times to "assist" her husband, not because she knew he was guilty but because she was convinced he was framed by police, prosecutor Tanya Smith said.
At the Lin house, Xie disconnected the electricity before making his way upstairs in the dark.
He then used a hammer-like object to inflict horrific head injuries on his newsagent brother-in-law, Min Lin, 45, and his wife, Lily, 43, as they lay in their bed.
He did the same to Lily's sister, Irene, 39, in the next room.
Blood splatters revealed a furious struggle took place in the third bedroom occupied by Xie's nephews.
But Henry, 12, and Terry, 9, still suffered the same shocking fate in the North Epping home.
"This was a well-planned crime of a personal nature, by a single person who has carefully improvised a murder weapon," Ms Smith said.
Xie believed he was entitled to respect and admiration within the extended family, but felt he was denied this because of the uncritical and misplaced high regard given to Min Lin.
"The Crown case is that this perception evoked intense emotions on his part, including anger and resentment."
The Crown also contended that Xie had a sexual motive, details of which cannot be published for legal reasons.
Four of the victims died from the combined effects of blunt force trauma and asphyxia, involving injuries indicative of neck compression.
The Crown cited Xie's medical skills, while Witness A, who was in jail with Xie, said Xie showed him a particular location on the neck, which was incapacitating.
Witness A also testified to seeing Xie, who always appeared calm in the dock, screaming at an elderly inmate who was using a walking frame.
"The whole [exercise] yard stopped," he said.
"It was like zero to 100."
Sentencing submissions are expected on February 10.