Police have charged a man with murder over the disappearance of Sydney schoolgirl Quanne Diec, who went missing in 1998.
The 12-year-old vanished on the morning of 27 July 1998 after she left her family's Granville home for Strathfield Girls High School in Sydney's inner west.
Quanne never showed up at school and the high-profile and baffling disappearance has remained a mystery ever since.
Police said on Monday said they had charged a 49-year-old man with murder in relation to Quanne's case.
The charged man turned up to Surry Hills Police Station about 3.40pm Sunday, wanting to speak to authorities, police said.
At the time Quanne went missing, police said her disappearance was out of character. In 1999, the NSW Government boosted the reward for information leading to the location of Quanne to $200,000.
In the years since she vanished, Quanne's elderly father Sam reportedly crisscrossed Australia in the hope of finding his daughter, while siblings Tina and Sunny prayed their sister would return home.
Police superintendent Scott Whyte told reporters that for Quanne's family the breakthrough represented a time of "mixed emotions".
"We have spoken to the family. They are very distressed. It is a time of mixed emotions. They are over the moon with police assistance but ... they are grieving and they would like some time alone," he said outside Granville police station.
Whyte said the charged man had been a suspect in the cold case for years, and did not rule out making further arrests. He said a search was currently underway in relation to the case at a local residence, but would provide no further details.
He said police believed it was not a random killing and that the alleged murderer knew Quanne before she went missing.
Whyte also paid tribute to officers who had worked on the case since 1998.
"It just goes to show how professional the police investigators are and they never stop, never give up ... I'm very proud to be commander of those officers."