BBC Scotland Investigates. What happens when the police act as judge, jury, and executioner? Mark Daly explores the astonishing story of the investigation into the death of Dunfermline man Drew Forsyth, in which police ignored witnesses, suppressed evidence, and misled prosecuting authorities in order to secure a conviction- a conviction which has since been overturned. Daly tracks down those responsible for one of Scotland's biggest miscarriages of justice in recent years.