The alleged attacker of a "vulnerable" victim bashed to death in a Sydney park has been charged with murder.
A 34-year-old man was refused bail after presenting himself to police for questioning on Monday over the alleged attack in Lurnea on Sunday.
William Guterres, 30, died in hospital shortly after he was found with serious head injuries.
Before charging the man, police said the pair had an extensive history.
Police believe Mr Guterres was set upon as he walked near his home.
"It certainly was a vicious attack and, in our view, a targeted attack on a specific person," Acting Superintendent Paul Albury told reporters in Sydney.
"Any attack on any vulnerable person is extremely concerning.
Police are also hunting two other men who they believe witnessed the assault from a nearby white ute and then left with the offender.
Investigators are hoping those two men - whose vehicle was captured on CCTV - will also come forward and help them piece together Sunday's attack.