One of Britain's most notorious teenagers, Luke Mitchell, was sentenced to life for the brutal murder of his 14-year-old girlfriend Jodi Jones. He was portrayed as the personification of evil. Now, as he prepares his appeal - and with the suggestion of a new 'suspect' - Frontline's Samantha Poling examines the circumstances under which Luke Mitchell was charged and reveals new information which casts doubt on the safety of his conviction.