The Murder of Arlene Arkinson

S1, E3: In 1994, 15-year-old Arlene Arkinson left her home to attend a disco in Bundoran, Northern Ireland. Her older sister waved her goodbye but would never see her again. This true crime documentary revisits this unsolved murder. Arlene's body has never been found, presumed to have been buried in the vast swathes of bogland on the Irish border. But who could be responsible for her death?