Mary Flora Bell was born in Newcastle upon Tyne on May 26, 1957, to Betty Bell, a seventeen-year-old who worked as a prostitute and who, according to family accounts given years later, tried more than once to kill or give away her daughter and repeatedly handed her to men. Mary grew up in Scotswood, a poor district of condemned terraces and derelict houses in which children played unsupervised.
On May 25, 1968, the day before her eleventh birthday, she strangled four-year-old Martin Brown in an empty house. The death was recorded as an accident; there were no marks and a bottle of tablets nearby suggested poisoning. Days later she and thirteen-year-old Norma Bell, a neighbour of the same surname and no relation, broke into a nursery and left notes claiming the killing in childish block capitals. Nobody took them seriously. Mary called at the Brown house and asked to see Martin, and when told he was dead said she knew, she wanted to see him in his coffin.
On July 31, 1968, the two girls killed three-year-old Brian Howe on waste ground known as the Tin Lizzie. He was strangled and there were small cuts on his body. Mary went back to the body afterwards with a razor blade and cut an M into his stomach.
They were tried together at Newcastle Assizes in December 1968. Norma was acquitted. Mary was convicted of manslaughter on grounds of diminished responsibility, the psychiatric evidence describing a child with classic signs of psychopathy, and was ordered detained at Her Majesty's pleasure. The judge called her dangerous. She was eleven.
There was nowhere to put her. She spent years in a boys' approved school at Red Bank in Lancashire, the only girl there, then in adult women's prisons from sixteen. She absconded briefly in 1977. She was released in 1980, aged twenty-three, and given a new identity.
She had a daughter in 1984 who did not learn who her mother was until reporters found the family. In 1998 Gitta Sereny published Cries Unheard, based on long interviews for which Bell was paid, and the payment caused a political row that reached the prime minister. In 2003 the High Court granted Bell and her daughter lifetime anonymity. That kind of injunction is now known in English law as a Mary Bell order, and has since been granted to Jon Venables, Robert Thompson and others.