Rising tensions between two groups have been blamed for an alleged machete murder of a teenager metres from his home.
Kon Hsu Sein was allegedly stabbed to death by a group of four males on December 20, 2024.
Cousins Ngor Agear, 24, and Myaker Myaker, 23, are among four people on trial in the Victorian Supreme Court after pleading not guilty to the 18-year-old's murder on Melbourne's western fringes.
In her opening address, crown prosecutor Erin Ramsay said the alleged victim and two friends were headed for a party when they left his family home in Kurunjang on the night of his death.
The trio were then confronted in a laneway.
Mr Sein's friends fled to safety but he was pursued into a nearby driveway and cornered by four males, three of whom were armed with machetes, Ms Ramsay told jurors.
Walking backwards with both arms in the air, the alleged victim yelled "back off, back off" as the quartet advanced on him, the jury was told.
Mr Sein's family wept in the courtroom as they watched and listened to CCTV footage taken from neighbouring homes showing surrounding streets.
The teenager suffered at least 20 chop and sharp force injuries during the one-minute attack, Ms Ramsay said.
His skull was fractured, his brain membrane impacted and his left hand was hanging, she said she expected the evidence to show.
Mr Sein had a knife with him, and that was likely used to stab two of the alleged killers during the fight.
The four accused were seen on CCTV running back to a car, which drove off.
They arrived at a health clinic with Agear suffering an eye injury and the youngest alleged killer having a deep cut on his left arm.
Neighbours rushed to help Mr Sein after hearing the commotion and called emergency services, but he died at the scene.
Air entering through the victim's gaping wounds in his head and face caused his pulmonary system to fail while blood loss also contributed to his death, the Crown said.
"The murder took place against a backdrop of rising tension between two groups," Ms Ramsay told the jury.
She said Mr Sein and his two friends were associated with one group while the two youngest alleged killers, aged 15 and 17 at the time, were associated with another.
The juvenile accused cannot be named for legal reasons.
Agear and Myaker, then aged 22 and 21 respectively, are not alleged to have been associated with any groups.
The crown case does not allege any single accused caused Mr Sein's death, but that the four were party to an agreement, arrangement or understanding to commit murder, and at least one of them caused his death.
Several of the accused quartet lied about their knowledge and details of the attack when speaking to police, Ms Ramsay alleged
Agear unknowingly spoke to a covert police operative, allegedly telling him the fight was about "beef" between the two groups.
The quartet's respective defence teams are expected to open their case later on Thursday.
