Mary Bell was 11 when she was given a life sentence in 1968 after being found guilty of the manslaughter of four-year-old Martin Brown, and Brian Howe, 3, on the grounds of diminished responsibility.

BBC: Child killer payment sparks law review

CNN's Ben Wedeman, Ben Brumfield, Marilia Brocchetto, Sarah Brown, Dugald McConnell, Brian Todd, Claudia Rebaza and Jason Hanna also contributed to this report.

CNN: March 19, 2013 -- Updated 1407 GMT (2207 HKT)

CNN's Susan Candiotti, Deborah Feyerick, Carol Cratty, Jake Tapper, Brian Todd, Pamela Brown and Kathleen Johnston contributed to this report.

CNN: 3 more detained in Boston attack