There is some connection in these people that is not there, it is broken. They, are broken. It's fascinating to study them, but they are still scary, still creepy. It all goes back to the empathy thing, or rather, the lack thereof.
One thing I remember from my college Abnormal Psych class, there is a part of the brain, the Amygdala, that plays a role in aggression. Also the Hypothalamus if IIRC. Also, these people have brains that do not respond to outside stimuli the same way as ours do, they require more. And they lack empathy, which makes it easy for them to commit the violent acts that they do. They do know the difference between right and wrong though. Thus, they're not legally insane, and are responsible for what they do.
Ijmo that CMJA is one of these people. What we don't know, is if given the opportunity / motivation, she would or would not, commit a similar act again. Given the level of violence she perpetrated against Travis, and given her disordered psychology, I personally believe she would. These type people are dangerous, she is dangerous, imo.