A murder charge against an elderly Queensland woman accused of killing her autistic son more than 50 years ago has been dropped after she passed away.
Maureen Anne Enright, 78, was charged in October 2020 with the murder of her son Peter, the fourth of her 11 children.
Peter was born on June 17, 1965, and police believed he died about three or four years later.
His parents Maureen and Michael Enright didn't report him missing when he disappeared in 1968 or 1969 aged three or four, a court had heard.
Police alleged Ms Enright murdered him at their Inala home in south Brisbane and may have had a hand in burying him in the yard.
An eight-day search in October 2020 of the family home and its surrounds - including digging up the yard and using ground-penetrating radar - did not find the boy's remains.
The family had been living at the property since 1966.
When Ms Enright was granted bail in November 2020, a Queensland judge labelled evidence against her as "practically non-existent".
She had spent about a month in custody before being released on bail.
"You have no effective cause of death, even if you did there is no evidence to sustain an intention to at least do grievous bodily harm," Justice Peter Callaghan said at her 2020 Brisbane Supreme Court bail hearing.
At the time her solicitor said there were physical and mental health concerns for Ms Enright who struggled to cope in custody due to a number of medical conditions.
The matter was repeatedly adjourned over the next two years due to her ailing health.
At a November 2022 mention, a court heard Ms Enright's health had deteriorated and there was a very slim prospect of it improving for her to appear at a committal hearing, with palliative care recommended.
The murder charge was formally dropped in Brisbane Magistrates Court on Monday after it was revealed Ms Enright had recently passed away.
Queensland Police confirmed that the matter could no longer proceed and it was finalised on Monday.
Ms Enright's husband Michael died in 2018.