Professor David Wilson, the UK's leading criminologist, presents the third series of Crime Files, this time focusing on Cold Cases. In episode 9, he looks at the concept of police confirmation bias and how miscarriages of justice can occur when police are selective about the evidence available to them.David goes to Dunfermline to examine the story of Andrew Forsyth from 1995 that led to one of the gravest miscarriages of justice in Scottish history and a former police officer being sentenced to 5 years in prison.David's first guest is Professor James Chalmers. An expert in miscarriages of justice, Professor Chalmers discusses how we all possess inherent bias and that police must work to recognise and lean into their bias to avoid targeting the wrong perpetrator and reduce the possibility of wrongful convictions.David, this series, is joined in studio by our resident Forensic Scientist Helen Meadows. Helen takes us through the evidence left behind after the murder of young woman Margaret McLaughlin in David's hometown of Carluke in 1973. David travels back there to examine the murder of the young woman who was taking a shortcut to the train station when she was stabbed 19 times and her body left in a wooded area. Despite what seemed an obvious false confession, George Beattie spent nearly two decades in prison for what many people believe was a crime he did not commit.In the studio, David speaks to former Scottish Crime Squad detective Bob Beveridge who was part of the investigating team at the time. He recalls carrying out house to house enquiries. David makes the case for someone he believes could have been responsible for Margaret's murder.