How science freed Kathleen Folbigg

She was once dubbed 'Australia's worst serial killer', after the deaths of her four children.  But now, Kathleen Folbigg is a free woman, after spending two decades in jail.  In a miscarriage of justice case reminiscent of the wrongful conviction of Lindy Chamberlain, the NSW Attorney-General has pardoned the 55-year-old after new scientific evidence emerged.  Today, ABC Background Briefing reporter Rachael Brown on Kathleen Folbigg's freedom and what it says about the judicial system.  Featured:  Rachael Brown, reporter, Background Briefing, ABC Radio National and ABC listen app