"We got him," Stanley's sister Joan said as she walked out of court.
It had taken 16 months, two trials and a gruelling 10 hour wait for the final verdict.
"Oh man, this feels so good. It feels massive," Ms Waipouri said.
Family and friends heaved sighs of relief and tears fell silently as the jury returned the verdict about 10pm. They had retired at 11.25am.
Murder accused Andre Gilling, 18, stood emotionless in the dock.
Ms Waipouri said it had been a long wait, but the result was worth it.
"This is what we wanted - justice. I would have wanted another hung jury rather than have a not guilty verdict."
She said there would never be closure as family wanted their brother back but this would allow them to keep on going.
Mr Waipouri, 39, who was gay, was found dead, naked from the waist down, in his Palmerston North flat on December 22, 2006.
He died from head and neck injuries after being kicked, punched and stomped to death for over an hour.
The tip of his penis and an earlobe were also missing.
Gilling, then 17, and Ashley Arnopp were found by police in the blood-stained flat and both were charged with murder.
During their trial in December, Arnopp pleaded guilty and the jury returned a hung verdict on Gilling.
Last week Gilling's retrial began in the Palmerston North High Court.
The court was told the men had been drinking alcohol, smoking cannabis and had taken party pills when they went to Mr Waipouri's Rangitikei Street flat.
It was the first time Gilling had met the victim, but Arnopp had been to his home before.
The prosecution alleged both Arnopp and Gilling were equally responsible with dna evidence linking them to the murder.
Both had "murderous intent" and were "feeding of each other's savagery".
But the defence claimed Gilling did not cause the fatal injuries because he was asleep in a drunken stupor and woke up during the attack.
Arnopp, a key witness for the prosecution - despite police refusing to pay him the $6000 he wanted to testify - said Gilling was the initiator and "proud" of his role in the killing.
The defence said Arnopp was a bitter liar and he was the only one responsible for the murder.
Phil Penwarden, a close friend of Mr Waipouri, said it had been hard listening to the indignities his friend suffered.
"If people want the definition of hate, read about the death of Stanley Waipouri," he said.
The trials had taken a huge toll on everyone and had been like "suspended animation".
He would be at sentencing on September 12 and hoped to read his victim impact statement.