The sister of a Ballarat teenager who vanished during a Murray River camping trip says she won't rest until she finds him.
Donny Govan is just one of the 35,000 people reported missing across Australia each year.
In September 2012, the 16-year-old vanished when an argument broke out during a family camping trip along the Murray River.
"We had been drinking so I couldn't drive him home and he just wouldn't take no for an answer and ran away," Donny's sister Rachael O'Keane said.
"Since then I haven't heard from him. I haven't seen him."
An extensive search failed to find any trace of the teenager.
"He's missed so much. He was an uncle three days after he went missing,"Rachael said. "Until we've got closure, we can't stop searching."
The only lead was from an 84-year-old great grandmother who was a convinced it was the Ballarat teen she cooked a hot breakfast for the day after he disappeared.
Detective Jason Hare, of Echuca Police, said: "At this stage we are unable to confirm if it was Donny or not. "We've had line searches, water police, and a police helicopter has been over the area on a couple of occasions."
Donny is one of nearly 5,000 Victorians, under the age of 18, reported missing last year, almost half were classified as high risk - meaning their disappearance is suspicious.
In conjunction with International Missing Children's Day, the Australian Federal Police are profiling a number of cold cases in the hope crucial information may come to light.
Rebecca Kotz, of the National Missing Persons Centre, said: "With every person that goes missing, there's at least two people who know where that person is.
"The person who goes missing and the person who has anything to do with it. So hopefully after all these years gone by, somebody has spoken about it."
The National Missing Persons Co-ordination Centre at the Australian Federal Police headquarters works with 22 other countries to profile thousands of children reported missing each year.
A smartphone app, Police Child ID, was also launched at a Melbourne event to help parents and guardians track down missing children.
Australian Federal Police Deputy Commissioner Andrew Colvin said 17,500 children were reported missing each year and the first 12 to 24 hours were critical.
"If we have accurate, good information straight away - photographs, dates of birth, habits of these children, friends, places they like to frequent - that gives police a good spot to start their investigation."