New evidence uncovered by Guardian Australia reveals that Queensland police failed to act on repeated and serious warnings about a man who perpetrated one of Australia's most shocking child abuse homicides.
The Tragic Death of Mason Jet Lee
Mason Jet Lee was 22 months old when he was punched in the stomach by his stepfather, William Andrew O'Sullivan – an ice user with a history of violent and controlling behaviour – in June 2016. The toddler's small intestine was ruptured, and he died a slow and painful death several days later, with no medical care. O'Sullivan and the boy's mother, Anne-Maree Lee, were jailed for manslaughter and child cruelty.
Mason's death has been the subject of at least seven government reviews, including an inquest. A coroner ruled that the handling of the boy's case by child safety officials was 'a failure in nearly every possible way' but made no adverse findings about the actions of police.
Withheld Evidence of Police Failures
Guardian Australia's Broken Trust investigation can now reveal the coroner's court also obtained evidence of serious police failures in the lead-up to Mason's death, but a coroner withheld it from the inquest. The information withheld includes police records showing how eight months before the boy was killed, a woman contacted police alleging that O'Sullivan had threatened to kill another child in his care.
After the woman's call, police placed a flag on O'Sullivan's file. However, the flag did not warn authorities about the dangerous man who would later kill Mason. Instead, it said any further requests for welfare checks of children should be treated by officers as 'vexatious' and referred to child safety authorities. The woman's subsequent attempts to warn police about O'Sullivan's alleged actions were ignored due to the flag.
Reactions to the Withheld Information
A lawyer who represented a child safety worker at the inquest was outraged when told of the withheld information by Guardian Australia and questioned: 'How can it be that we never even knew this had happened?'
The Killer's File Flagged
In the immediate aftermath of Mason's death, much of the public narrative focused on two alternate villains: the child safety department and the boy's mother, Anne-Maree Lee. Mason had been living in Caboolture with O'Sullivan at the time he was killed, while Lee lived nearby. There was public outrage that a mother would leave her child in the care of a violent man.
An internal investigation into child safety failures resulted in disciplinary action against several staff working in a system that was severely understaffed. O'Sullivan, who delivered the fatal blow, and Lee, who was not there at the time, pleaded guilty to manslaughter and child cruelty. Both were sentenced to nine years in prison; O'Sullivan's sentence was increased to 12 years on appeal.
Domestic Violence Death Review Unit Report
When the inquest began in 2019, Queensland's domestic and family violence death review unit prepared a report for the coroner that detailed O'Sullivan's significant history of domestic violence and coercive control. It is understood the report challenged the public narrative about Lee and explained her inaction in the context of that violence and control. The report also found evidence of serious policing failures, specifically that police had placed a flag on their system and ruled concerns about O'Sullivan 'vexatious'.
The coroner's court refused to release the report to Guardian Australia. However, summaries of the report's conclusions have been obtained by reviewing anonymised case studies published by the DFV death review board. The summaries confirm the existence of the police flag and detail that a woman called police for help after O'Sullivan allegedly 'kidnapped her child and threatened to kill himself and the child'.
'The investigating officer flagged [O'Sullivan's] file to reflect, without any clear rationale or explanation, that any further requests for welfare checks of children were vexatious and should be referred to Child Safety Services,' the summaries say. 'There were indications that subsequent police responses to concerns of child abuse and domestic and family violence were influenced by this point-in-time assessment of the victim's motivation.'
Plans to 'Skin' Woman
O'Sullivan had a 20-year criminal history, the inquest was told, which included drug offences and probation breaches. It was also told he had a history of perpetrating violence against Lee and previous partners. An unpublished submission to the inquest, seen by Guardian Australia, says that in April 2015 he presented to hospital with suicidal and homicidal thoughts, including threats to kill children and to 'skin' a woman. This was the same woman whose warnings were – about five months later – dismissed by police as vexatious.
The submission reveals that O'Sullivan had been taken to hospital on that occasion 'in the company of police' but this fact was omitted from the inquest finding. It is unclear whether the police who escorted him to the hospital made any records. But significant information about O'Sullivan's history would have been available to the officer who ultimately dismissed the allegations about him as vexatious. To date, the decision to put a flag on his file has never been investigated.
In a statement to Guardian Australia, the Queensland police service did not address specific questions about the decision but said the force had conducted 'a full and thorough investigation' into Mason's death that resulted in the manslaughter and child cruelty convictions. 'The QPS is committed to continually reviewing its processes and working with partner agencies to better protect and support community members impacted by domestic and family violence,' a spokesperson said.
Did the Coroner Ignore Police Inaction?
In other cases – such as the inquest into the murders of Hannah Clarke and her three children – the pre-inquest review by the death review unit has been critical. In that case the coroner, Jane Bentley, embedded the entire review in her findings. However, at the Mason Lee inquest, the unit's report was received but not included as evidence by the former deputy state coroner John Lock.
Guardian Australia has seen an email from Lock's counsel assisting to lawyers involved in the inquest, confirming that the coroner's court held information obtained by the death review unit but that it would not be distributed or included in evidence. No explanation was provided in the email as to why this decision had been made, and the coroner's court did not address questions seeking an explanation.
Susan Moriarty, a lawyer who represented a child safety worker at the inquest, said she was never told about the 'vexatious' flag and only learned about it when contacted by Guardian Australia. The state government had 'hunted down the hapless, overworked, under-resourced and inexperienced social workers involved in this case', she said. But Moriarty asked why evidence of police failures had not received the same scrutiny. 'I don't mean to be disrespectful but did the coroner ignore police inaction to go after the low-hanging fruit, the social workers?' Moriarty said. 'It is agonising to know that had police not labelled [the woman]'s repeated notifications 'vexatious' that Baby Mason may be alive today.'
Worried About Mason Getting Hit Really Hard
Lock, who made the decision not to rely on the DFV death review unit's report, resigned unexpectedly for unrelated reasons after the inquest began. Bentley then took over. The inquest heard no evidence about the flag on O'Sullivan's file. 'I make no adverse findings in relation to the involvement of any member of the Queensland Police Service involved in this matter,' she ultimately found.
But her conclusion overlooked other apparent police failures detailed within the body of the findings. The findings state that on 24 March – about two months before Mason died – a police officer and child safety officer interviewed another of Lee's children. The child disclosed that O'Sullivan was violent to her mother and that she was 'worried about Mason getting hit or punched by a bad guy and he might die'. Another sibling was 'worried about Mason getting hit really hard if he cried so she tried to look after him', the child said. The child safety officer and the police officers 'chose to simply ignore what she had said and move on to their next question', the inquest findings noted.
When contacted by Guardian Australia, the coroner's court said it did not provide media comments related to cases before it. 'This is because coroners speak publicly through their findings and rulings which form part of the coronial investigation (including inquests), in relation to which appeals may be conducted,' a statement said. 'It is inappropriate for coroners to add to or detract from what they have said other than as part of their findings.'



