Police failed to act on repeated warnings about a violent man before he killed a toddler. But that’s not the most shocking thing about this case

Nine months before the death of the toddler Mason Jet Lee , a woman called police to warn them about the boy’s killer, William Andrew O’Sullivan. They placed a flag on his file labelling the woman’s claims “vexatious”. But that’s not the most shocking part of this story. Police already had evidence O’Sullivan was suicidal and homicidal. Months earlier they’d gone with him to a hospital, seeking mental health treatment, and while there he threatened to “skin” the woman and kill children. But that’s also not the most alarming thing. The coroner’s court was aware of these policing failures but decided to withhold the evidence from an inquest. That such information could be buried from the many reviews and investigations into Mason’s death has caused serious concern. And yet is still not the most significant revelation from the Guardian’s latest Broken Trust investigation . What our reporting on this case shows is clear: this is not a breakdown of the system that is supposed to protect children, investigate deaths and correct failures. This is the system working as designed. The officer who labelled the woman’s concerns about O’Sullivan as “vexatious” was following approved Queensland police service policy. The QPS operational manual instructs officers, when deciding whether to undertake a welfare check on a child, to assess four criteria. One of those is “any motive or advantage that a notifier may receive” from police involvement. …