A judicial inquiry into Kathleen Folbigg's convictions for killing her four children has been told the NSW Director of Public Prosecutions (DPP) accepts new evidence points to the possibility of reasonable doubt.
Folbigg, 55, who has been called Australia's worst female serial killer, has five years remaining of a 25-year sentence, after being convicted in 2003 of three counts of murder and one of manslaughter.
Her children Laura, Sarah, Patrick and Caleb all died suddenly on separate occasions between 1989 and 1999, aged between 19 days and 19 months.
Retired Chief Justice Tom Bathurst KC is hearing closing submissions after months of evidence in a second judicial inquiry, after the convicted mother exhausted all avenues of appeal in the courts.
Sophie Callan SC, one of three lawyers assisting the inquiry, said the evidence overall shows there is reasonable doubt about Folbigg's convictions, and a strong plausible case for each child's death.
"Ms Folbigg urges Your Honour to find reasonable doubt and the strong possibility of innocence," Ms Callan said.
According to Ms Callan, the DPP has presented submissions to the inquiry suggesting it is now possible to conclude "there is reasonable doubt about Ms Folbigg's guilt".
DPP Sally Dowling SC declined to comment on the case.
Ms Callan said evidence about a rare gene mutation Folbigg shared with her two daughters, but not her sons, CALM2G114R, must be seen as casting doubt on her convictions for killing Laura and Sarah.
Ms Callan said other medical evidence about seizures and epilepsy must be seen as casting doubt on her convictions for killing sons Patrick and Caleb.
She said psychiatric and psychological expert evidence presented to the inquiry has cast doubt on Folbigg's diary entries used to convict her at trial.
Ms Callan told the inquiry Folbigg "had a major depressive disorder and was expressing maternal grief" when she wrote about struggling with motherhood.
This is a vastly different view to the one presented at her 2003 criminal trial, in which the diary entries were seen as expressions of guilt.
Ms Callan said the evidence had shown that the long held view Folbigg smothered her children was "an inherently unlikely prospect".
Ms Folbigg's lawyer, Robert Cavanagh, told the inquiry his client was a woman who loved her children and who had suffered vilification in the media.
"Her privacy has been demolished," he said.
"Every moment of her life has been recorded.
"This would be enough to break any person, but she maintains strength and the belief that one day the truth will be told."
Test case for law reform
For the first time since the quashing of Lindy Chamberlain's murder conviction, science has nudged the judiciary in the Folbigg case, with the new gene mutation evidence.
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.
If Mr Bathurst finds reasonable doubt, he could refer the case to the Court of Criminal Appeal to consider quashing Folbigg's convictions.
Mr Bathurst could also recommend a pardon, which would see Folbigg walk out of jail.
The closing submissions continue.
