Explained: Why scientists want ‘Australia’s worst female serial killer’ to be pardoned

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“Not to do so is to continue to deny Ms Folbigg basic human rights,” the petition read. Their argument is based on the full genome sequencing of Folbigg and all four of her children. The scientists found that two of Kathleen’s children inherited an unreported genetic mutation from her, which could have led to their death.

Who is Kathleen Folbigg?

Folbigg, 53, was arrested in 2003 following a seven-week trial in which she was convicted of smothering her four children — Caleb, Patrick, Sarah and Elizabeth — over a ten-year period during moments of frustration.

The death of her son Patrick, who died at eight months in 1991, was initially believed to have been due to asphyxia after an epileptic fit. The deaths of Sara and Caleb, aged 10 months and 19 days respectively, were both attributed to Sudden Infant Death Syndrome, also known as SIDS. In 1999, Laura died at 19 months old in 1999, but the cause of death was never ascertained.

Folbigg has always maintained her innocence and insisted that her children died due to natural causes. Her conviction was based largely on circumstantial evidence found in journals she had maintained around the time that her children died.

In one entry from 1997, written soon after her daughter Laura was born, Folbigg said, “Wouldn’t of handled another one like Sarah. She’s saved her life by being different.” She added, “She’s a fairly good natured baby, thank goodness, it will save her from the fate of her siblings. I think she was warned.”

“With Sarah all I wanted was her to shut up. And one day she did,” another entry read. Folbigg was said to have shown no emotions during her trial, which was said to have coloured public perception of her.

In 2019, the New South Wales government announced an inquiry following a petition by her supporters. The inquiry, led by Justice Reginald Blanch, upheld her conviction. In a 500-page report, Blanch said that the evidence “does not cause me to have any reasonable doubt as to the guilt of Kathleen Megan Folbigg for the offences of which she was convicted”.

But her attorneys have argued that convictions for crimes as serious as murder cannot be based solely on circumstantial evidence.

Her case is being compared to that of Lindy Chamberlain, who was pardoned 32 years after being convicted for the murder of her baby Azaria. A coroner later ruled that the baby was taken away by a dingo.

Why are scientists petitioning for Folbigg to be pardoned?

The group of scientists and medical experts pushing for Folbigg to be pardoned have argued that her children died due to a rare genetic defect. The group comprises noted experts in the field of medicine and genetic disorders, including Nobel Laureate Peter Doherty, Nobel prize winner Elizabeth Blackburn and former Australian of the Year Fiona Stanley, ABC news reported.

The petition is based on a study which looked at the full genome sequencing of Folbigg and her four children. Genome sequencing of Sarah and Laura’s DNA, pulled from their neonatal heel prick tests, showed that they had both inherited a genetic mutation from their mother called CALM2.

According to the experts, CALM-2 mutations are known to cause sudden death due to cardiac arrest. Folbigg’s sons Caleb and Patrick’s genomes showed a different genetic mutation, which may have also contributed to their deaths, the scientists claimed. They both possessed a variant of the BSN gene, which has been linked to lethal epileptic fits.

The boys’ medical history also indicated a link with the scientists’ findings. Patrick was diagnosed with epilepsy four months before his birth, while Caleb had difficulty breathing due to a floppy larynx. Further research is being conducted into their genomes.

The study was carried out by a team of scientists from around the world and published in a peer-reviewed cardiology journal called Europe, two years ago.

What happens if Folbigg gets pardoned?

If pardoned, Folbigg’s convictions will not automatically be overturned. Rather, she will still have to appeal her conviction in the NSW courts, ABC news reported.