Fiolar, I share your forebodings. Of course what they did was horrific. I just hope that their detention was put to good use, that they weren't just locked away. The years of adolescence are by and large the time of biggest change in any person's life, so if they've had adequate help there is a chance that they have grown into responsible people who will never do wrong again. (There are examples of this in other child killers. One has become a successful novelist.)
However, those who clamour for them to be locked away for life don't see it that way. I understand little Jamie's family reacting less than sensibly, but everybody else ought to take a step back and ask themselves what they are doing. They're interfering, not with justice, for in such cases there can be no justice, but with the law.