Homicide Squad detectives are appealing for public assistance as the investigation continues into the death of Solomone Taufeulungaki in Deer Park earlier this week.
Emergency services were called to an incident on Neale Road shortly after 4pm on Tuesday, 16 June.
The 15-year-old Deer Park boy had been stabbed during the incident and died at the scene.
Six teenage boys aged between 13 and 16 were arrested a short time later and all six have subsequently been charged with violent disorder and affray.
A 15-year-old boy presented himself to police on Wednesday night and was also charged with affray.
At this time, no one has been charged with Solomone's death and the investigation remains ongoing.
Detectives believe the fatal affray was as a result of tensions between two youth gangs in the western suburbs and have identified the gangs involved.
Police have been told the groups have been involved in a number of other incidents over the past few weeks, including a significant altercation in Warringa Crescent, Hoppers Crossing on 23 May.
Investigators are also looking at an assault which occurred at the Brimbank Shopping Centre, at the corner of Neale and Station Roads in Deer Park, the day before the fatal affray.
Officer in charge of the Homicide Squad, Detective Inspector Tim Day, called on members of the groups involved to speak up for Solomone.
"This is an act of senseless, cowardly and extreme violence in public and in daylight hours," he said.
"It's resulted in the death of a teenage boy who had his whole life ahead of him - his family will never see him grow up, finish school, have a career, create a family of his own.
"We know there are members of the groups involved in Solomone's death who are uncomfortable with what has happened and that the actions of a few have gone too far, and this is their time to speak up for him.
"Police need your assistance. Investigators have spoken to a large number of people, however we are certain that there are other people who witnessed the assault who have not yet come forward.
"It's also likely that those witnesses or those involved have spoken to family, friends of associates about what happened when Solomone was killed, so we're really calling on those people to do the right thing and come forward as well.
"If you want to speak to police then we can arrange this and there is also the opportunity to provide information confidentially via Crime Stoppers.
"Again, this is your time to speak up and I cannot be clearer that this investigation is far from over."
Detectives believe a number of people involved in or who witnessed the affray have mobile phone footage of the incident and are appealing for those people to contact police.
Police would also like to hear from anyone who was driving in the vicinity of Station and Neale Roads in Deer Park between 3.30pm and 4.30pm on Tuesday 16 June who may have captured dash-cam footage of the incident.
Frontline police, with support from the Public Order Response Team, Mounted Branch, Transit police and PSOs, have been proactively patrolling shopping centres and community locations in the City of Brimbank throughout the past week to ensure people feel safe, and are safe.
Victoria Police is here to support the community and we encourage residents to engage with police officers and share any concerns they might have.
Anyone with information or any footage in relation to the fatal affray is urged to contact Crime Stoppers on 1800 333 000 or make a confidential report at www.crimestoppersvic.com.au
