WHEN an eight-month-old William Tyrrell arrived at the home of his new foster parents, it was an arrangement that was always intended to be permanent.
The baby boy had been removed from his biological parents - both of whom had encountered problems with police - and placed in the care of foster parents.
His biological father was a career criminal who had spent most of William's short life incarcerated.
It is understood his biological father and mother, Karlie, whose name was released this week after a ruling in the NSW Supreme Court, have been linked to domestic violence-related incidents.
However, these occurred after William had been removed from their care and there is no suggestion either were ever violent towards him.
It is understood William's foster agreement with his new parents in Sydney's northern suburbs was intended to be a permanent arrangement.
Justice Brereton also raised "the tragic probability that (William) is no longer alive".
His biological mother was aware of the intention.
Before his disappearance in September 2014, William did have supervised visits with his mother, contrary to some media reports.
However it's understood these visits were infrequent and that William identified his foster family as his parents and was known to the public by their surname (which can't be disclosed) and not "Tyrrell".
The new revelations come as the identity of Karlie Tyrrell has been revealed in the wake of a ruling by the NSW Supreme Court which has allowed the fact that William was in foster care to be disclosed for the first time.
In his ruling, Justice Paul Brereton noted there was "substantial public interest" in the integrity of the out-of-home care system. In making his decision, Justice Brereton also raised "the tragic probability that (William) is no longer alive".
"Moreover, the truth has, to date, been obscured: the public has admittedly been given to think that (his) carers are his parents.
"There is a substantial public interest in accountability and scrutiny of the out-of-home care system, and in accuracy of reportage of the circumstances of his disappearance," he said.
The ruling was made just over two years after his shocking kidnapping from a mid-north coast home during what was a visit to his foster grandmother.
William and his parents were paying her a visit as she had recently begun transitioning to a new life following the death of her husband.
William, aged three at the time, was snatched while playing on his grandmother's front lawn.
His body has never been found and his abductor never charged.
William's distraught family, who have never been named for legal reasons, have been unrelenting in their quest to see justice served.
The investigation into his disappearance is "very much ongoing", according to police, but neither his foster family nor his biological parents are suspected of any involvement. William's grandmother has since moved.
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