Any studies on psychology of SCAMMERS, not victims?

From my amateur take on psychology, it seems scammers are all narcissitic type personalities

But there are different types of narcissists... vain, rage, self-righteous, and entitlement

It seems the last two are the ones that motivate scammers. Any one know more about psychology than a layman want to comment? Or can point to some studies or articles on this matter?

I am mainly going off this

http://www.psychologytoday.com/blog/...ed-controversy

Which is more about marriage / divorce than scams, but it seems to apply.