The mother of a teenage boy who was allegedly killed over a pair of headphones has described her son as "a kind person with a happy spirit".
Jason Galleghan, 16, died in hospital from serious head injuries in August.
Police say he was lured to a home before being bashed to death in Doonside, in Sydney's west.
Kayla Dawson, 19, four teenage boys aged between 13 and 15, and a 15-year-old girl were charged with murder and remain before the courts.
Ms Dawson's boyfriend, Harley Bartolo, 29, was arrested at a block of units in Werrington earlier this month and charged with being an accessory after the fact.
Investigators have released new CCTV vision of two men they want to speak to in relation to the fatal attack, which was filmed and put on social media.
The men are seen wearing hooded jumpers with mobile phones in their hands.
"Police are particularly interested in speaking with the two individuals who may have been walking in the vicinity of the home on Perigee Close, around the time of the fatal attack," Superintendent Steve Egginton said.
"I urge anyone with information, no matter how insignificant you believe it to be, to come forward and contact Crime Stoppers."
Jason's mother, Rachel Galleghan, spoke publicly for the first time since her son was killed, saying she was still coming to terms with the loss.
"Jason was such a kind person with a happy spirit; he was loving and generous and helpful to his sisters and to his family and friends," she said.
"It's just so utterly devastating and heartbreaking that his future has been taken away from him.
"We have lost the biggest part that can never be replaced."
Ms Galleghan also thanked the community of Doonside for their support and urged them to keep fighting for Jason "so that justice is served".
Detectives released CCTV of another man seen leaving the crime scene earlier this month, but so far there has been no further arrests.
