One of Britain's youngest killers walks among us today, completely anonymous.

After serving only 11 years in jail for the brutal manslaughter of 4-year-old Martin Brown, and 3-year-old Brian Howe, she was released at the age of 23.

No one will ever know the whereabouts of a woman who, at the tender age of 11, took the lives of 2 young boys.

This is the story of child killer Mary Bell.