I could go along with those also....serial killers are typically psychopaths or sociopaths...they know what they are doing is wrong at the time, even plan on doing it, and lack empathy. Kidnappers and torturers to me have a similar mindset as long-term abusers...and they often, if not always, torture their victim to death and are probably serial in nature.
Mass shooters I am a little more hesitant on....simply because it can be a pure emotional crime and I think a life sentence without parole would impact them more harshly.