My brother Steve has schizophrenia. He used to live in a house with Patrick, who had schizophrenia and was also a psychopath. How do I know? Whenever I went around there he got in my face, like within two millimeters of my face, with a huge grin. And then he murdered his mum.
There was a particularly awesome moment during a weird Christmas party there when Steve told Patrick, "Not meaning to be rude or anything Patrick, but you're a c--- : in a strictly business quality sense." (Said in his usual quite quiet and not confrontational voice...)
So if the killer in CT had Asperger's, as some have been suggesting, he also was a psychopath. Asperger's is irrelevant, just as schizophrenia was irrelevant to Patrick's psychopathic behavior. You can have two conditions at once.