The attack occurred shortly before 9pm on Friday in the transport precinct near Westfield Mount Druitt. The victim, a Sydney father on his way home from work, had stopped to speak with a group of young people he knew as family friends. Concerned about how they would get home, he went to withdraw cash from a nearby ATM. It was then that another group of young people took offence to the interaction, police said.
Mount Druitt Police Area Commander Darrin Batchelor said the victim was stabbed twice. "Another group of young people took offence to the conversation the 36-year-old male was having with those young people, and as a result of that we now stand here with that 36-year-old murdered," he said. The attack was witnessed by 12 other young people, according to police.
Detectives used CCTV footage to identify the 13-year-old suspect. He was arrested when he arrived at Mount Druitt Police Station on Sunday night to report as part of his bail conditions for a separate offence. Police allege he was already in breach of that bail at the time of the stabbing. He has been charged with murder, breach of bail, and an unrelated robbery charge.
A second boy, aged 16, was arrested at his home in Cabramatta on Sunday evening and charged with accessory to murder after the fact. Police recovered the knife from a drain outside the boy's apartment, Commander Batchelor said.
At least two other young people present during the attack are expected to be charged. Batchelor urged them to surrender, saying they were allegedly involved in the assault of the victim.
Police are treating the killing as a random, chance encounter, though the investigation is also examining potential gangland links. Superintendent Brendan Gorman of Blacktown Police Area Command said the victim was believed to have been known to police. "It's a horrendous incident, concerning for police," he said.
Both arrested teenagers spent Sunday night in custody and were scheduled to appear in a children's court on Monday.