Investigations are underway into whether an altercation with three other cars contributed to a "catastrophic" crash that killed four teenagers less than 10 minutes later.
Four teens, including the 16-year-old driver, and passengers aged 15, 16, and 17, died after their Ford sedan lost control and hit a small truck at Truganina about 7:30pm on September 30.
The sedan had six young men inside and none were wearing seatbelts.
Police say there is "nothing at this time to indicate any culpability" on behalf of the 28-year-old truck driver, who was also injured in the crash.
The Homicide Squad has been called in to assist Major Collision Unit investigators, with police now looking into an incident minutes before the crash.
At 7:22pm, police say "some type of altercation" occurred involving people inside three other vehicles, a red Volkswagen Golf GTI, a blue Volkswagen Golf R and a red Holden VF Commodore.
Each of the vehicles contained "a number" of men.
In CCTV footage, the sedan driven by the 16-year-old boy is boxed in by three cars on Derrimut Road outside Tarneit Shopping Centre.
The sedan reverses, as several people jump out of the other vehicles and run towards it. It then crosses to the other side of the road and speeds off.
Police are investigating whether the incident is connected to the deadly crash and whether it contributed to "the way the victim's vehicle was being driven".
They are asking for anyone who was near Derrimut Road at that time to come forward.
At the time, Assistant Commissioner of Road Policing Glenn Weir described the crash as "catastrophic".
Australian Associated Press