Police say witnesses of the fatal stabbing of a teenager at the Sydney Royal Easter Show could be staying silent over "misguided loyalty".
Uati ‘Pele’ Felatolu, 17, who worked for one of the show's ride operators, was stabbed in the chest last week in front of stunned onlookers, during a brawl between two groups.
NSW Police have yet to identify the killer despite trawling through hours of CCTV and mobile footage before and after the fight which happened about 8pm last Monday.
Detective Superintendent Danny Doherty said there was likely a "final bit of the jigsaw puzzle" out there that could help solve the 17-year-old's alleged murder.
"We do know there was a large amount of footage...people filming, if not the incident, but the brawl straight after," Detective Superintendent Doherty said.
"Footage may be incredibly vital to help solve this murder...it's not the time to stay silent....how someone (did not) notice who (was) responsible for this murder is beyond me."
Detective Superintendent Doherty said witnesses may have unknowingly recorded something that could help investigators, or associates could be keeping "staunch".
"It's been a week since the murder. Whether (staying silent) is through misguided loyalty....it doesn't help us, it's disappointing and frustrating," Detective Superintendent Doherty said.
He said a tip that the fight was between two warring gangs from separate Western Sydney postcodes was a "strong line of inquiry" being investigated.
A 15-year-old relative of Mr Felatolu, who was allegedly in possession of a knife at the scene, remains before the courts.
It was alleged in court that he produced the knife as he came to the aid of his 17-year-old family member, who was being attacked.
A 16-year-old boy underwent treatment for a wound to his leg.