Sydney man Haysem Charbaji hurled foul-mouthed abuse at his victim's family after he and his brother were found guilty of stabbing and bashing Dane McNeil before his body was set alight in a suitcase.
Charbaji and his brother Azam Charbaji who often appeared to be amused during their month-long trial, were found guilty of the 2014 murder, largely due to the horrific evidence given by Mr McNeil's friend Brendon Gallo.
After hearing the verdict on Wednesday, Haysem Charbaji turned to Mr McNeil's family and shouted "f***ing dumb dog", while Azam smiled and winked to his supporters.
The brothers stabbed, bashed and force-fed Mr McNeil Xanax tablets over a weekend of violence before his smouldering body was found stuffed in a suitcase in a park in Sydney's south.
The 20-year-old died of a combination of multiple stab wounds and the toxic effects of drugs.
Lexy May Jamieson, 26, was found guilty of being an accessory.
"Everyone was taking ice, everyone was a supplier of ice to some degree or another," prosecutor Margaret Cunneen SC told the NSW Supreme Court jurors.
Outside court, Mr McNeill's father Peter warned about the dangers of ice.
"He was only on ice for a short term but in that short term he went from a soft-hearted ... beautiful person to getting into the wrong crowds and stuff," Mr McNeill said.
"Unfortunately he paid the price for it and I can't tell people enough to stay off the ice."
Mr Gallo, who said he no longer used the drug, said the violence began when the four men returned to the flat shared by Haysem Charbjai and Jamieson.
When Mr McNeill asked for money, saying he was going to be bashed if he did not pay a debt, the brothers punched him repeatedly.
Mr Gallo sobbed as he described seeing his 20-year-old friend being attacked, stabbed and force-fed Xanax.
Mr McNeill was tied up and placed in the laundry overnight and taken to Azam Charbaji's house the next morning where they all smoked ice again.
Although he admitted having many opportunities to get help, Mr Gallo said he had been afraid the brothers "would turn on me".
He heard his friend screaming and crying for help when the pair took him into the bathroom.
He later saw Azam Charbaji retrieve a 20cm-long ratchet from a tool box before hearing "three bangs and more screaming".
He was told to buy cleaning products and the large suitcase used to transport the body to the park at Picnic Point.
Mr Gallo poured a mixture of petrol and kerosene onto it before setting the suitcase alight.
Another witness, whose name was suppressed, told police Jamieson had asked for advice about cleaning up the flat and disposing of a body.
His reply was to "go cook it, burn it, get rid of the DNA" and "you need to contaminate the scene, you need to throw animal blood all over it, you need to use sulphuric acid".
The judge continued Jamieson's bail while the brothers remain in custody, until the trio's sentence hearing on December 2.