Kathleen Folbigg spent 20 years in prison after a jury found she killed sons Caleb and Patrick and daughters Sarah and Laura over a decade.
But a recent inquiry heard scientists believe they may have died naturally.
The 55-year-old’s case has been described as one of Australia’s greatest miscarriages of justice.
Folbigg, who has always maintained her innocence, was jailed for 25 years in 2003 for the murders of three of the children, and the manslaughter of her first son, Caleb.
Each child died suddenly between 1989 and 1999, aged between 19 days and 19 months, with prosecutors at her trial alleging she had smothered them.
Previous appeals and a separate 2019 inquiry into the case found no grounds for reasonable doubt, and gave greater weight to circumstantial evidence in Folbigg’s original trial.
But at the fresh inquiry, headed by retired judge Tom Bathurst, prosecutors accepted that research on gene mutations had changed their understanding of the children’s deaths.
On Monday, New South Wales Attorney General Michael Daley said Mr Bathurst had concluded that there was reasonable doubt that Folbigg was guilty.
As a result, the NSW governor had signed a full pardon, and ordered Folbigg’s immediate release from prison. (BBC)
