Mary Bell

On 25 May 1968, the day before her 11th birthday, Mary Bell strangled 4-year-old Martin Brown in a derelict house. She was believed to have committed this crime alone. Between then and a second killing, she and a friend, Norma Joyce Bell (1955–1989; 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 two girls took part in the strangulation death of 3-year-old Brian Howe on wasteland in the same Scotswood area. Police reports concluded that Mary Bell later returned to his body to carve an "M" into the boy's abdomen and used scissors to cut off some of his hair, scratch his legs, and mutilate his genitals.

On 17 December 1968, at Newcastle Assizes, Norma Bell was acquitted but Mary Bell was convicted of manslaughter on the grounds of diminished responsibility. The jury took their lead from her diagnosis by court-appointed psychiatrists who described her as displaying "classic symptoms of psychopathy". The judge, Justice Cusack, described her as dangerous and said she posed a "very grave risk to other children". She was sentenced to be detained at Her Majesty's pleasure, effectively an indefinite sentence of imprisonment. She was initially sent to Red Bank secure unit in Newton-le-Willows, Lancashire – the same facility that would house Jon Venables, one of James Bulger's killers, 25 years later.

After her conviction, Bell was the focus of a great deal of attention from the British press and also from the German magazine Stern. Her mother repeatedly sold stories about her to the press and often gave reporters writings she claimed to be by her daughter. Bell herself made headlines in September 1977 when she briefly escaped from Moor Court open prison, where she had been held since her transfer from a young offenders institution to an adult prison a year earlier. Her penalty for this was a loss of prison privileges for 28 days.

In 1980, 23-year-old Bell was released from Askham Grange open prison after serving 12 years and was granted anonymity (including a new name), allowing her to start a new life. Bell allegedly came back to Tyneside on several occasions and had lived there for some time after her release. Four years after finishing her sentence she had a daughter on 25 May 1984. The girl knew nothing of her mother's past until reporters discovered Bell's location in 1998 and the pair had to leave their home with bedsheets over their heads.

Bell's daughter's anonymity was originally protected only until she reached the age of 18. However, on 21 May 2003, Bell won a High Court battle to have her own anonymity and that of her daughter extended for life. Consequently, any court order permanently protecting the identity of a convict in Britain is sometimes known as a "Mary Bell order". The order was later updated to include Bell's granddaughter (b. January 2009), who was referred to as "Z". Bell's current whereabouts are unknown.

Bell is one of thirteen child killers reported on in the book Children Who Kill: Profiles of Pre-teen and Teenage Killers by author Carol Anne Davis, published in 2004.