CSI based documentary serieswhich uncovered the tragic history of Britain’s young murderers, including the horrific cases of Jamie Bulger & Mary Bell. On 25 May 1968, the day before her 11th birthday, Mary Bell strangled four-year-old Martin Brown in a derelict house. She was believed to have committed this crime alone. Between that time and the second killing, she and a friend, Norma Joyce Bell (no relation), aged 13, broke into and vandalised a nursery in Scotswood, leaving notes that claimed responsibility for the killing. The police dismissed this incident as a prank. On 31 July 1968, the pair took part in the death, again by strangling, of three-year-old Brian Howe, on wasteland in the same Scotswood area. Police reports concluded that Mary Bell had later returned to his body to carve an “N” into his stomach with a razor this was then changed using the same razor but with a different hand to an “M”. Mary Bell also used a pair of scissors to cut off some of Howe’s hairscratch his legs, and mutilate his penis. As the girls were so young and their testimonies contradicted each other, the precise details of what happened has never been entirely clear.