Loner — how unsurprising.
Because, of course, loner = sociopath; well other than Charles Manson, or J.W. Gacy, or Ted Bundy, or Dylan Klebold/Eric Harris, John Mohammed/Lee Malvo, etc, etc. There's no shortage of outgoing, personable individuals who go out and do reprehensible things. Then when their crimes come to light they become shunned by former friends and tossed in solitary by the justice system - then like it or not they really do become loners.