Cries Unheard: Why Children Kill: The story of Mary Bell (1998) by Gitta Sereny is the result of a collaboration between Mary Bell & writer Gitta Sereny.

Mary Bell was convicted of 2 counts of manslaughter in December 1968 when she was 11 years of age.

Gitta Sereny spent something like 5 months interviewing Mary Bell after she was released from prison in May 1980 at the age of 23.

She explored the abuse & neglect Mary Bell had experienced as a child and thought her crimes could be explained by this.

Apparently Sereny paid Mary Bell for those 5 months of interviews, which led to a public outcry as there was concern that a killer was profiting from her crimes.