It says all traits used to count toward a diagnosis of psychopathy must be backed up by evidence. I suppose it an offender could be completely non-violent, having rather been convicted of other serious crimes that have screwed many people over. That's fine.
It doens't say how much evidence or what evidence it need,s just that it should have some. And gives examples of some types.
I used to think I was a sociopath, but it turns out I'm actually only a colossal jerk. I've not killed anyone though. Wait... do kids count? I don't think they should, I mean, they haven't really been alive long enough to be considered people, right? Anyway, I hate those little bastards, always smiling...