A lifelong friend and supporter of Kathleen Folbigg, jailed for killing her four children, says her friend is hopeful a petition by some of Australia's leading scientists will help clear her name.
Tracy Chapman, who visits Folbigg weekly in jail on the mid north coast of NSW, has long campaigned for the release of her friend.
"Kathleen and I are thankful that the focus is now on solid evidence-based, peer reviewed science in relation to this case, rather than on subjective coincidence and circumstantial evidence," Ms Chapman told AAP.
Folbigg, 53, has spent 18 years in jail for murdering Patrick, Sarah and Laura, and for the manslaughter of her son Caleb.
The petition signed by 90 "world leading scientists" has called for a pardon and Folbigg's immediate release, and says there is compelling evidence she did not kill her children.
The research identified a mutant gene that was carried by two of the Folbigg children which could have led to their deaths.
The list of petitioners includes president of the Australian Academy of Science John Shine, Nobel laureate Professor and former Australian of the year Peter Doherty, and Nobel Prize prize winner Emeritus Professor Elizabeth Blackburn.
Former Australians of the Year Professor Fiona Stanley and Professor Ian Frazer - who invented the cervical cancer vaccine - and former chief scientist Professor Ian Chubb, also signed the petition.
During her trial, the prosecution argued Folbigg smothered her children and said it was unlikely the four infants could die suddenly and unexpectedly in their sleep. She was also convicted on circumstantial evidence from her diaries.
Campaigners have long maintained that Folbigg used her journals for exactly what they were designed for, to write down random thoughts as therapy.
In March 2019, there was a judicial inquiry into Folbigg's convictions after forensic pathologists raised concerns over medical evidence.
That inquiry, led by former Chief Judge of the District Court Reginald Blanch, upheld the conviction and concluded the inquiry produced "evidence that reinforces Ms Folbigg's guilt".
However, the petition states that during the inquiry, the genomes of the Folbigg children were sequenced and it was found that the two girls had a novel mutation in the CALM2 gene.
Mutations in this gene are one of the best recognised causes of sudden death in infancy and childhood, both while asleep and awake.
The petition said the case against Folbigg was "entirely circumstantial" and there was "no medical evidence to indicate smothering".
"It is based on the proposition that the likelihood of four children from one family dying of natural causes is so unlikely as to be virtually impossible. This flawed logic, otherwise known as 'Meadow's Law', permeated the trial and the 2019 inquiry."
Tracy Chapman has been friends with Folbigg for almost 50 years, and told AAP the petition has given Kathleen new hope.
"Kathleen said that it's not just about her case anymore, it's for all mother's, all parents, so that this never happens to another woman or family again," she said.
"It's nearly 18 years since she was first convicted but even if this attempt isn't successful, we'll keep fighting, because the truth never lies."
A spokesperson for the NSW Attorney General Mark Speakman said the petition would be given appropriate consideration, and noted that Folbigg's convictions had been examined in two appeals to the Court of Criminal Appeal, a special leave application to the High Court and an inquiry.
"As the Attorney General will make a recommendation to Her Excellency the Governor to resolve the petition, it would not be appropriate for the Attorney General to provide further comment at this stage," they said.
Australian Associated Press