It's a hard topic- liability of a teenager for crimes they commit, how they should be treated (as a minor who can be rehabilitated or as a lost cause and dangerous adult), how their brains work, is there ever hope for a teenager who commits a crime like this.
On the one hand I think science shows that teenager's brains are quite different from adults. They lack the capacity of adults. Which society has determined should result in less harsh sentences (death penalty and LWOP is outlawed for teens now).
On the other hand, science also seems to show that the brains of a psychopath are far different than everyone else, and that this is established in childhood. So depending on the ruthlessness and sophistication of he crime, society has determined that some teens should be treated as adult criminals, or as close to such as possible.
I read that according to some experts in psychopathology, children's brains are more malleable and it's possible that treatment of kids with "callous-unemotional" traits can prevent them from becoming full-fledged psychopaths. And teenager's frontal lobes aren't developed yet. So there might be hope.
However, the study I read had to do with the treatment of 4-8 year olds - not 15. And while we are debating how to treat someone like this young killer, we should remember that Todd Kohlepp was also 15 when he kidnapped and raped a peer. And this was after 6 years of treatment as a child. Then, upon being arrested, and after 25 months of extremely intensive intervention in jail and then 14 years in prison, the last 9 years of which he didn't exhibit disciplinary problems, he went on to murder at least 7 people, possibly more, and rape and kidnap a few women.
I think the bottom line is every teenager is different. If they commit a crime the courts should consider:
1. Do they exhibit callous unemotional traits?
2. Are they particular sophisticated or cunning compared to other kids their age?
3. Have they exhibited violent behavior previously?
4. Have they been treated to no avail?
5. How ruthless and savage was their crime?
6. What do brain scans/psych evals say about their psychology, neurology and whether or not they can be rehabilitated?
I don't think one size shoe fits all.