The mother of a Victorian teenager who died after being assaulted by gatecrashers at a party never got to say goodbye to her son.
Jason Langhans, 17, died in hospital on Saturday following a fight during a 16th birthday party at a home in Melbourne's southeast on March 21.
Police believe Jason was hit twice in the head with a screwdriver at 2.30am after trying to stop the altercation involving three male gatecrashers, who arrived as the Tooradin party was winding down.
Jason's mother Carolyn said she woke up to his mate knocking at the family's door with her son falling in and out of consciousness in a car.
They called triple-zero and he was taken to hospital within 10 minutes, but died three weeks later.
"I never got the chance to say goodbye," Ms Langhans told reporters on Thursday.
"I'm devastated - my heart is broken. I've lost my son and he's not coming back.
"I don't know how a human being could ever do something like that. It's cowardly ... horrifying."
Ms Langhans said Jason was an "outdoorsy" boy who loved fishing, camping and four-wheel-driving with his mates, as well as playing football for local team Narre Warren.
The 17-year-old had signed up for an apprenticeship, bought a car and "just loved life".
"He was a loving, caring, gentle person," Ms Langhans said.
She urged the three gatecrashers to hand themselves in to police.
Detective Inspector Andrew Stamper said other party guests chased the unknown trio from the property before another scuffle broke out nearby.
Police have yet to locate the weapon used, believed to be a screwdriver.
The three men of interest are believed to be of driving age and are not from the surrounding area, Det Insp Stamper said.
They all wore dark clothing to the party.
"I can't even imagine what the Langhans family must be going through, to find out that your son and much-loved brother, who just went out to a party, will no longer be coming home," Homicide Squad Detective Inspector Andrew Stamper said in a statement on Thursday.
"From the information we have at this stage, this fatal assault appears to have occurred without provocation, and was an attack on a young man without warning."
Det Insp Stamper urged anyone with information to come forward.
"To the friends or guests who chased the trio away, who would have been just trying to look out for their friend, we'd like to hear from you to help establish the circumstances of what occurred, and you may be able to help us find the weapon involved," he said.
"We're urging anyone who knows the three men involved, who we believe attended with the intention to cause trouble, to come forward.
"These men need to be held to account for their actions."
