Kathleen Folbigg has served 20 years of a 25-year sentence for crimes she says she did not commit.
But within months, Folbigg will learn if there was "reasonable doubt" with her convictions, that could lead to a pardon.
The 55-year-old was convicted of smothering her babies Caleb, Patrick, Laura and Sarah on separate occasions between 1989 and 1999, but has always maintained they died of natural causes.
Retired New South Wales Chief Justice Tom Bathurst KC will now sift through the volumes of evidence experts in the fields of science, psychology, and psychiatry submitted to the inquiry.
For decades the retired judge has sat on appeal panels that found holes in matters of law, such as decisions made by other judges and prosecutors, things not explained properly to juries or sentences incorrectly applied.
This job is a slightly different one, presiding over a judicial inquiry.
"It's not my role in this inquiry at all to conduct a review of how the trial was conducted," Mr Bathurst said on Thursday as the proceedings finished.
Instead, Mr Bathurst's job is to decide if there is reasonable doubt about Folbigg's convictions, and to send a report on his decision to the Governor.
He can recommend a pardon, and he can also send the matter back to the court of appeal to consider quashing the convictions.
Crucial evidence previously unavailable
The former judge told the inquiry there is now a significant body of evidence available to suggest Folbigg's children died of natural causes, and said his final report is likely to state people "can't be criticised for their reasoning" when Folbigg stood trial in 2003.
Mr Bathurst said the evidence before him now did not exist at Folbigg's trial, when she was convicted of three counts of murder and one of manslaughter.
It was a circumstantial case, largely based on diary entries which were seen as admissions of guilt.
Folbigg's diaries were given to police by her husband Craig, whose lawyers submitted to the inquiry that "the dominant feature which remains in this case is the fundamental implausibility of the hypothesis that four children in one family died of natural causes before reaching the age of two-years".
Tom Bathurst also told the inquiry, a now abandoned line of reasoning known as 'Meadow's Law', that suggested three or more sudden infant deaths in a family was murder until proven otherwise, influenced the trial.
Two decades later, psychiatrists and psychologists have for the first time analysed the diary entries, telling the judicial inquiry that rather than admissions of guilt they were written by a depressed, grieving mother struggling with parenthood and profound loss.
Possible causes of death
The other key pieces of evidence M Bathurst has been forced to digest are complex expert accounts about a recently discovered rare gene mutation, which causes heart problems and sudden death in children.
Kathleen Folbigg shared this gene mutation with her daughters Laura and Sarah, but not her sons.
Other medical conditions such as seizures have been suggested at the inquiry as possible causes of death for Caleb and Patrick.
Dean Jordan, representing the NSW Director of Public Prosecutions, told the inquiry some of the new evidence was "beyond the contemplation of science" at the time of Folbigg's trial, and fundamentally changed what prosecutors understood about the deaths of her two daughters.
Similarities to Chamberlain case
Folbigg's barrister, Gregory Woods, likened her case to Lindy Chamberlain's wrongful conviction for the murder of her daughter Azaria.
Lindy Chamberlain was eventually acquitted years after new evidence was found.
"Such is the case here. Those involved at earlier stages did not have all the evidence, which this case has now," Dr Woods said.
The inquiry has shown how forensic science and police investigative procedures are changing rapidly, but the judiciary moves at a slower pace.
Testing the need for law reform
This matter is being watched as a test case for the need for law reform in Australia.
Countries such as the UK, New Zealand, Scotland, and Norway have introduced "Criminal Case Review Commissions" to deal with post-appeal phase new evidence, but Australia has not.
Long-time friend Tracy Chapman has come to the inquiry every day, and says Folbigg feels relieved to have finally been heard.
"Kath is nervous it will all go down the path it has before and her convictions won't change, but also more hopeful than she has been before," Ms Chapman said.
"If Australia gets a new Commission to deal with post-appeal new evidence, because of this inquiry, it will help others in Kath's situation and her time in jail won't be for nothing.
"I just want her to come home."
The inquiry has now finished, Mr Bathurst said he will deliver a report to the Governor, Margaret Beazley, as soon as possible.
