The "perfect storm" of dangerous psychology, which Ronni mentions, is a good way to describe my use of the term the "dark triad" which I have borrowed and adapted from some very technical psychological research. The dark triad is a name for this linkage of three traits that are closely related but also distinctive: Machiavellianism, narcissism, and psychopathy. One could say extreme manipulativeness, a malignant form of self-centeredness and psychopathy.
Although Ronni quotes me, I like her description: "Psychopaths, we know about. Daumer. Bundy. Duncan. These "cold killing machines" who have no empathy. The thing about Peterson that didn't fit this label was the fact that he had never been in trouble before. Psychopaths tend to get in trouble with the law early in life, and stay that way. Not all of them, of course, but most. The narcissist, on the other hand, is not usually a killer. He likes to reinvent himself, and he needs a constant supply of adoration and positive reinforcement, but his usual pattern is to just disappear when the supply dries up. However, when Machiavellianism is added to the mix. The Machiavellian is a master manipulator."
Cases in my book which explore in detail these traits include Scott Peterson (of course), L. Ewing Scott (made his wife 'disappear' in mid-fifties Los Angeles), Perry March (Nashville), Robert Durst, John David Smith (husband of Fran Gladden Smith of New Jersey), Justin Barber, and many others.