Is there a movie about the child killer Mary bell?

Answer 1

No, I don't think there ever will be, out of respect to the deceased childrens family's.

Bell is the subject of two books though by Gitta Sereny;The case of Mary Bell (1972), an account of the killings and trial, and Cries unheard, the story of Mary Bell (1998), an in-depth biography based on interviews with Bell and relatives, friends and professionals who knew her during and after her imprisonment. This second book was the first to detail Bell's account of sexual abuse by her mother, a prostitute who specialized as a dominatrix, and her mother's clients. Cries unheard was controversial because Bell received payment for her participation. The payment was criticised by the press, and the government attempted to find a legal means to prevent its publication on the grounds that a criminal should not profit from his or her crimes, but the attempt was unsuccessful. The law has now been changed so that criminals cannot profit from their crimes. Bell's case was used as the basis for a 1999 episode of Law and Order entitled "Killerz". Hallee Hirsh played the Mary Bell analogue.

In the related links box below, There is the documentary.