Oh, I have not read about an amazing cover up of the crime. Isn't it the consensus of the thread that UnSub got "lucky" by being at the right place at the right time?
Therefore, it remains a targeted killing or targeted sex crime that ended horrifically. This creep is a dangerous sexual sadist, jmho. He probably stalked VM for a long time. The point is that VM, herself, in particular, was the specific target of the perp's fantasies.
Perp's IQ depends. Many loners are psychopaths b/c they cannot find balance within a relationship. Think John Hinkley. Theirs is a life typically filled with turmoil, angst, and drama. Jealousy. Paranoia. Revenge. Holds a grudge. Impulsive.
Whereby, sociopaths (Think Orenthal.), by their very nature, are social individuals who usually are successful CEOs and entrepreneurs. They are typically the risk takers, money movers and shakers and can be great organizers and negotiators. Both diagnosis could be suitable for a highly intelligent personality.
Often, in cases like this where the brutality of overkill is overwhelming and brazenly conducted, for example, during midday hours, NPD is also a factor.