obviously, this is a classic psycopath or sociopath. he's a sick pup!
...not necessarily.
If I were his defence lawyer I'd have him tested for all possible mitigating circumstances:
-concussion damage/atrophy with the central brain (common among violent offenders with poor impulse control)
-viral (meningitis) brain damage
-altered brain chemistry
-full liver metabolite tests (some people produce an LSD analogue within their livers)
-ergot poisoning (it's a fungus that grows on grain and causes everything from violence to cannibalism)
-alcohol/ethanol psychosis (some people can have a sip of whiskey and wake up three days later having
killed their whole family and chewed off their own fingers)
-altered choline metabolism (acetyl-choline cascades are the leading candidate for explaining classical Lycanthropy ("werewolfism") animal behaviour in humans)
-early stage porphyria (a genetic disorder which, coupled with outbreaks of ergot poisoning, was the historic basis of the vampire legend)
...the depravity of the crime would seem to warrant further study, not that such medical conditions condone such actions... but they might legally reduce the offenders culpability.
The Luke