The man accused of murdering two Aboriginal children in remote NSW town of Bowraville in the 1990s will not face a retrial.
He was previously acquitted in separate trials of killing two of the children: four-year-old Evelyn Greenup; and 16-year-old Clinton Speedy-Duroux.
No one has ever been charged with the murder of 16-year-old Colleen Walker.
The families were hoping all three cases could be tried together, and have been waiting 10 months for the court to come to its decision.
The man, who cannot be named for legal reasons, faced the possibility of a new trial after 'double jeopardy' laws were reformed allowing a new exception for 'fresh and compelling' evidence.
On Thursday morning, the NSW Court of Criminal Appeal dismissed the application for a retrial because it was not satisfied that 'fresh and compelling' evidence had been produced.
'Fresh' evidence means that it is 'new' and could not have been presented at the original proceedings.
Prosecutors hoped to put forward evidence about Colleen Walker’s disappearance but the court decided it did not meet the criteria because it was available at the time of the two previous trials.
“We recognise the distress that the deaths of these children and the subsequent investigations and proceedings have caused the families involved,” the court said in its judgement.
“This application was not a retrial of the respondent for any of the charges of which he was acquitted; nor was it an appeal from such acquittals.”
The court also noted it had not determined the guilt or innocence of the alleged offender.
'It didn't feel right'
As the decision was read in court, there were audible gasps and sobbing from the families sitting in the gallery.
"It felt really cold the way they read the judgement. Like no respect for the families. I know it's legal talk and they have to be impartial, but it didn't feel right," Leonie Duroux told NITV News.
Outside court, Greens MP David Shoebridge told NITV News the families have been “let down again” by the criminal justice system.
“This is not finished,” he said. “In the meantime, we’ll sit with the lawyers, we’ll sit with the families to see if there’s anything and we’ll consider if there’s any possible appeal to the High Court.”
Mr Shoebridge said he had been hopeful the attempt to order a retrial would succeed and that he could not imagine how the families were feeling after the decision.
“I see a political failure as much as a legal failure today,” he said.
Clinton Speedy’s aunt, Dolly Jerome, was in tears after the decision.
“I’m absolutely disgusted and appalled at the system,” she said.
“I don’t know how any of this works. But I do know that my nephew’s life was just as valuable as anybody else in this country. Why should he be disregarded? Why?”
Clinton Speedy’s nephew, Marbuck Duroux, said he was "devastated" by the decision.
"I'm cold and speechless," he said.
He left a series of ochre handprints on the windows of the Law Courts building in Sydney, and chanted 'What do we want? JUSTICE!'
“It’s not the first time we’ve got knocked back, so you try not to get your hopes up,” he said.
“It’s something we’ve sort of always seen coming which is sad but that’s the judicial system, especially for blackfellas, I suppose.”