Who Stabs A Six Year Old To Death?

From June 6, 2014 CBS News comes a horrifying report of a six year old stabbed to death, and his seven year old friend who survived.  A 27 year old is being held.   The story tells us what is doubtless the root cause:

The station reports the suspect also has nine prior arrests, including two for assaulting police and correction officers. Court records state he was arrested in May 2009 for punching his mother in the face and wrapping an electrical cord around her head. After that, he was sent to a psychiatric facility for seven months.

I rather doubt that the courts sent him there because they were feeling generous.