I think we are getting hung up on the MO thing. There is no rule that the perp has to fallow the exact tactic every time. Military snipers are pretty adaptable, (scope mounted M-2) the only thing they are going to do his consistent with killing and escaping to kill again. MOs work with nut jobs mainly because they are driven by compulsive behavior. This guy could be very sane, just wrong.
If he is a pro, changing MOs would have an advantage.
"This guy could be very sane, just wrong."
He may be more of a sociopath, just doesn't care.