Convicted killer Arthur Boycott Greer will be released from jail in Western Australia after 25 years behind bars and deported to the UK.
The 80-year-old murdered Sharon Lee Mason, 14, who disappeared in Mosman Park in 1983 and whose body was found nine years later, buried behind a shop previously owned by Greer.
Greer's next statutory review date was scheduled for November next year, but he wrote to the Prisoners Review Board in October seeking an early review because of his failing health.
The board determined Greer's old age, deteriorating health and limited mobility reduced his risk of reoffending, and Attorney-General John Quigley accepted its recommendation to release him.
"Information pertaining to Greer's current state of health was critical to my decision making," Mr Quigley said.
Ms Mason's family has been advised.
"Ms Mason's loved ones expressed a wish that Greer be transported from prison to deportation and that he not taste freedom in Australia again," Mr Quigley said.
"Arrangements are being made for Greer to leave as soon as possible for the UK, relinquishing WA taxpayers from the ongoing cost of his 25 years of incarceration and compounding medical needs."
In 2003, when Greer was aged 65, the family asked then Attorney-General Jim McGinty to release him so he could be deported.
But the board said he was a sexually-predatory psychopath and the risk of reoffending was too extreme for him to be set free.
His criminal history includes three convictions of attempted murder and numerous sexual assaults.
Shadow attorney-general Michael Mischin said the release of Greer and the reasons given were "a betrayal of everything that people expect from our criminal justice system".
Greer had always denied responsibility for Ms Mason's death and refused to cooperate with police.
"If it hadn't been for the accidental discovery of her body, she'd still be missing and her parents would be wondering what happened to her," Mr Mischin said.