Teenagers accused of killing a man outside an apartment block have been extradited from interstate and charged with murder.
Emergency services were called to Pitt Street in the inner-southern Sydney suburb of Waterloo about 7.20pm on August 18.
Officers found a 34-year-old man with stab wounds who was taken to hospital in a critical condition.
The man, who police identified on Friday as Blain Locke, died around an hour later.
Superintendent Andrew Garner said he had spoken to Mr Locke's devastated family.
"No arrest can undo the loss or their suffering," he told reporters on Friday.
"It's a senseless act of brutal violence. It impacts the entire community."
Supt Garner said Mr Locke did not know the alleged offenders but there was a broader association between the two groups.
"It may have related to an ongoing issue," he said.
The stabbing took place after a confrontation in front of the apartment block, Supt Garner added.
A 35-year-old woman, who was with Mr Locke at the time, was also allegedly attacked and suffered cuts to her face.
Following what Supt Garner described as a complicated investigation, two men - both aged 18 - were arrested by Queensland Police at a property in Toowoomba.
They were extradited to NSW and each charged with murder and wounding someone with the intent of causing grievous bodily harm.
One of them was 17 at the time, NSW Police said, and did not receive bail when he fronted Children's Court on Friday.
Meanwhile, the other 18-year-old faced court where he did not apply for bail and was formally refused.
Police then arrested a third man, aged 20, on Morehead Street in Redfern, in inner-city Sydney, on Thursday afternoon.
He was also charged with murder and wounding a person with intent to cause grievous bodily harm.
The 20-year-old also made no application for bail.
All three men will return to court in December.