Relatives of three Aboriginal children who disappeared in Bowraville nearly 30 years ago have vowed to fight on after the High Court refused to hear an appeal relating to their suspected killer.
The NSW Court of Criminal Appeal in September rejected an application by the state's attorney-general for the man to face a single trial charged with three murders.
The High Court on Friday refused to grant special leave to the government to appeal the decision.
"We can find no reason to doubt the correctness of the decision of the Court of Criminal Appeal," said Chief Justice Susan Kiefel, sitting with Justices Virginia Bell and Stephen Gageler.
After the decision, angry supporters put painted handprints on the glass outside the building and screamed for justice.
Four-year-old Evelyn Greenup, Clinton Speedy-Duroux, 16, and Colleen Walker, 16, disappeared from the northern NSW town over a five-month period from September 1990.
The man, who can't be named for legal reasons, was acquitted of Clinton's murder in 1994 and of Evelyn's murder in 2006.
In the appeal court, the government unsuccessfully argued there was fresh and compelling evidence - relating to the disappearance of Colleen - to justify the overturning of the two acquittals and the ordering of a single trial on three murder charges.
Under NSW double-jeopardy laws revised in 2006, a person can be tried for the same crime for which they have already been acquitted provided there's fresh and compelling evidence.
Outside the High Court on Friday, Evelyn Greenup's aunt Michelle Jarrett said the families will never give up the fight for justice.
"This is not the end of the road for us," she said.
"We will be coming back, we will be petitioning the NSW government to support David Shoebridge's double jeopardy law."
The Greens MP told reporters the case was "a gross injustice" and his proposed amendment to the law "opens up a very narrow and fresh gateway for the families in Bowraville".
The current situation was not the fault of three judges of the High Court or three judges of the appeal court, but a "collective failure of the criminal justice system and parliament", Mr Shoebridge said.
Gavin Stanbrook, a relative of Colleen Walker, said the family was "disgusted" with the decision, lamenting that "there is still a murderer out there and we want justice for our children".
NSW Attorney-General Mark Speakman said the result was disappointing.
"Today's decision represents yet another blow to the children's families, who have bravely fought for justice over the last three decades," he said in a statement.
"I am sorry for the further trauma and grief today's decision will bring."
Australian Associated Press