A QUEENSLAND court was told of serious allegations linking Maree Crabtree to her daughter's death two years before she allegedly murdered her son.
The Queensland Civil and Administrative Tribunal overturned a decision to remove Jonathan Crabtree from his mother's care just months before his alleged murder, despite allegations of her conduct being raised in court.
The Courier-Mail yesterday revealed Jonathan Crabtree's father Mark had launched a desperate bid to have his son placed in the care of the state's Public Guardian.
The move was initially endorsed by QCAT but in September 2016, the same court set aside the decision on appeal, effectively granting Maree Crabtree guardianship of her son.
Within months, Jonathan was dead.
It sparked a renewed effort by Queensland police, culminating in this week's dramatic arrest of Crabtree, who is accused of poisoning her disabled children Jonathan, 26, and his sister Erin, 18, at their home on the Gold Coast, as well as a host of torture, fraud and robbery charges over a five year-period.
In allegations which have shocked the nation, Crabtree is accused of forcing the children to take prescription medication and portraying their deaths as suicides as she claimed life insurance payouts worth about $1 million.
She also allegedly enjoyed an exotic cruise holiday with Jonathan and another family member who cannot be named, while Erin lay dead in their Riverstone Crossing home.
Victims embroiled in QCAT family matters cannot be identified while they are alive but it can now be revealed that Mr Crabtree made a successful application for a guardian and administrator to be appointed to care for Jonathan in 2015, as he recovered from a serious car accident.
The initial QCAT hearing was told of "very serious allegations" implying Crabtree was involved in Erin's death in 2012 and questions were also raised about her actions and behaviour immediately after Jonathan's 2015 car crash.
However, the subsequent appeal ruled that none of the allegations were properly "analysed ... in the reasons for decision" and the original verdict was set aside.
The applications were to be returned to QCAT for reconsideration by a different panel, but nine months later, Jonathan was dead.
A source close to the investigation said detectives never believed Erin's death was suicide and tried desperately to have Jonathan, who suffered serious head injuries in the crash, placed in the care of the Public Guardian.
"The system failed him," the source said.
After Crabtree's court appearance in Brisbane this week, her lawyer said she would vigorously defend the charges.