Kathleen Folbigg, 55, was convicted in 2003 for the murder of three of her children and the manslaughter of a fourth child. The prosecutor's office accused her of suffocating the children between the ages of nine weeks and three years.
A year-long investigation revealed "reasonable doubts" about the case. The material suggested that the children had died naturally due to rare genetic abnormalities, a judge said in a ruling on the case on Monday. The state of New South Wales has pardoned the mother.