Maree Mavis Crabtree faces a string of charges including counts of murdering her daughter Erin, 18, in 2012, and son Jonathan, 26, five years later.
Both siblings had disabilities, with police alleging they died from being forced to take prescription medication.
It is alleged Crabtree claimed disability and insurance payouts relating to the siblings.
The 54-year-old is also charged with attempting to murder Jonathan six months before his death, and the torture of a woman, aged in her 20s.
Erin was found dead in their Maudsland home in September 2012, while Crabtree was on a cruise.
Crabtree was charged with murder six months after Jonathan died.
A woman, who cannot be named, earlier told the committal hearing in Brisbane Magistrates Court she first told police Jonathan killed himself after being given bad news the day before.
She agreed when questioned by defence barrister Angus Edwards the bad news was that Jonathan was going to have to go into a respite home.
Jonathan had been seriously injured when he drove into a tree a few years before his death in July 2017. The crash initially left him on life support and facing months of rehabilitation.
Two-and-a-half years after Jonathan died the woman wrote a Facebook post that prompted officers to visit her.
She then told them Crabtree had killed Jonathan.
“I’d … changed my mind and decided to tell what really happened,” the woman told the committal hearing.
Edwards said the woman told police Crabtree gave Jonathan a drink with OxyNorm in it.
Asked if she remembered that at the time she told police he died by suicide, the woman admitted she originally lied to the police.
“But I wasn’t thinking clearly back then,” she added.
“I was under a lot of stress and I couldn’t think straight and probably did tell some lies, but now I am telling the truth.”
After the hearing lasting less than three weeks, Crabtree was committed to stand trial on two charges of murder, one of attempted murder and one of torture.
She is also facing a number of counts of fraud and attempted fraud.
Her trial will be held on a date yet to be decided.Jump to next article