'Do not trust anyone with your kids who aren't family'. The words of Malachi Subecz' mother, who from behind bars, says that's a harsh lesson she's learnt in the worst possible way.

Malachi's mum trusted Michaela Barriball to care for her boy, when she was sent to jail. Barriball tortured, and murdered him.

Today, some children's advocates say the five-year-old was not "invisible" in the months before he was murdered.

They say there were not only red flags, there were flashing neon lights. It's just no-one in authority took action.

But some are warning mandatory reporting could actually put children at greater risk.

Ruth Hill reports.