What really worried me about Logan's child murderer, was that the boy had an obsession with death and killing people. He had been in care and his carers had expressed worries and had had him moved, yet Social Services returned him to a highly dysfunctional home,m seemingly with no concerns about his abnormal mind set.
The loss for Ava's family is infinite, but the boy involved doesn't seem to have had a death obsession.
Even for children, life is life - in that they will be under supervision, and able to be called back to prison anytime for the rest of their lives. The 15 year prison sentence, just means the minimum sentence they must serve.
One of the boys involved with the murder of James Bulger, has been recalled back to prison several times.