For 31 years, the heartbroken mum of murdered schoolgirl Nikki Allan never gave up her quest for justice.
Sharon Henderson, 56, turned detective in her desperate search for the seven-year-old's killer, begging the Chief Constable of Northumbria Police for help.
She told how the terrible mistakes made in the original 1992 investigation left Nikki's killer David Boyd at large for more than 25 years.