The psychopath

Individuals with this personality disorder are fully aware of the consequences of their actions and know the difference between right and wrong, yet they are terrifyingly self-centered, remorseless, and unable to care about the feelings of others. Perhaps most frightening, they often seem completely normal to unsuspecting targets and they do not always ply their trade by killing.
. . . con artists, hustlers, rapists, and other predators who charm, lie, and manipulate their way through life.
http://student-guide-to-forensic-psychology.blogspot.com/2007_06_01_archive.html
Most people, fed by the Hollywood idea, imagine the psychopathic individual to be very flamboyant, a highly intelligent sort of Hannibal Lecter. But that isn't the type of individual you're seeing. . . . a callous disregard for others, and a cold, bewildering cleverness. They also reveal a calculating desire to harm. They're serial killers. . . . the mind of the remorseless . . . classic, antisocial behaviour that you think of when you think of psychopathy - doing consistent harmful acts to other individuals - and also some pronounced emotional problems, so they don't feel guilt. It's very common amongst normal murderers to feel very guilty about the people they've actually hurt, after the offence. Psychopathic individuals: you just don't care.
Dr James Blair is a neuropsychologist at University College, London, says “Most psychopaths wouldn't be serial killers. They're certainly not motivated to go out and kill. They may kill somebody because that person gets in the way, but there's no desire to go and hurt another human being.”
There's nothing about psychopathy that's linked with intelligence. Impairment of emotion, yes.
Stuart Kinner is a forensic psychologist and researcher at the University of Queensland. Probably the pin-up boy for psychopathic people is Ted Bundy in some respects. He's clearly a very charming guy, clearly a very remorseless guy, and clearly a very manipulative guy. He also was a serial killer, which is another thing altogether. lack of emotion, that coldness, that callousness. What you often find with psychopaths is that after a few meetings, you start to realise that they're not all they seem to be. Underneath their veneer of charm, underneath their veneer of knowledge, they're often a very uninformed, very insincere person. Quite often, the people who I guess would be psychopathic, they do (to put it simply) give you the creeps a little bit when you meet them. They're often the same people who try to be very charming, who try to tell you a story, and they'll fixate their eyes on you while they tell you this story, because all the while they're just checking, have they managed to convince you, have they managed to manipulate you. . . . But as regards whether it's a fundamental problem caused by a specific set of genetic information, or whether it was caused by a particular environmental trauma, at a specific age; that question at the moment we just have no answer for.
There's a lot of research in the last 5 to 10 years, showing that psychopaths have a much more coercive much more aggressive sexual strategy, and they're also much more promiscuous and start having sex earlier in life. . . . if they're passing on their genes, then it could follow that they're increasing the percentage of psychopaths in the general population . . . When you think about it, it's very hard for a psychopath to con another psychopath. A psychopath won't trust someone else, so we have to have a lot more victims than psychopaths out there, for them to be successful. This is why they tend to be relatively nomadic, why they tend to move from city to city and from community to community.
Being a psychopath works if you're a man. You can move from community to community, you can spread your genes widely by mating with a whole variety of people, and moving on. Unfortunately, the woman is left to look after the child, and that does tend to happen quite a lot. The same traits that lead to psychopathic personality behaviour in men may be present in women, but quite often they manifest differently, and women are less likely to be predatory, they're more likely to be self-harming than harming others, in fact, with similar traits.
. . . Psychopaths . . . don't respond to fear or sadness, and they don't experience guilt or remorse. Teaching people to think more about other people's emotions, teaching them about empathy, teaching them to think about other people, is actually just increasing their ability to manipulate and con others. . . . our culture, especially youth culture, is desensitised and emotionally detached and exploitative and sensation-seeking. . . . parasitic lifestyle, for example, which is one of the diagnostic criteria for psychopathy. But you know, the charming, superficial interpersonal style, the lack of remorse and guilt, and shallow affect . . . is being encouraged in today’s society.
From http://www.abc.net.au/rn/allinthemind/stories/2002/511461.htm