There are some folks who don't believe in good or evil. I'm not one of them, for the obvious Christian reasons.
You need to understand that "evil" falls within the field of Axiology and that most scientists who are Methodological Naturalists don't typically think science has much to say on morality, (unless they're like Sam Harris), other than to perhaps apply surveys to see how people think about morality and to insist that when running experiments and presenting results, honesty must play a part in the reporting process.
In other words, scientists aren't going to put "evil" in a test-tube and qualify it or break it down and analyze it. No, this activity is relegated to Theology or to Philosophy; and these are the areas in which, and by which, people discern and categorize the conceptual qualities of good and evil. Otherwise, if we're doing science, we're just studying animal and human behavior and don't---and probably shouldn't---- have much to say about the subject. [And again, I'm aware that there are atheistic neuro-scientists out there now, like Sam Harris, who are attempting to bridge this formerly unbridged chasm and bring morality into the realm of science and pull it away from Theology and Philosophy.]
However, being that scientists are also, existentially, human beings apart from their doings of science, they can muse about Ethics and Morality too, just like everyone else, and when they do so, they take off their lab coats and put on their philosophy tennis shoes in order to qualify their own personal evaluations about "evil" [or good].
And no, mankind is not the only one who generates evil or the recognition of evil. Some animals of higher order intelligence know something about misconduct, just not to the extent, obviously, that human beings do.
No, you're simply misunderstanding the specific nuance I'm addressing in regard to sociopaths and psychopaths as outside the norm of human behavior. I'm not saying that only sociopaths and psychopaths sin and do evil; what I am saying is that when they do so, they don't care that they do so.
...... I asked you for sources FIRST. But whatever the case, I'm sure both you and I can dig up some relevant sources. For now, I'll give you one of the sources that's listed in my CF personal page:
Science, Life and Christian Belief -- Malcolm A. Jeeves & R.J. Berry (1998)
Right. From within the bounds of science, I'm not going to say that scientific theory can account for evil. For me to account for evil requires the Logic(S) of both Theology and Philosophy. And if neuro-scientists (like either Malcolm Jeeves or Sam Harris) want to attempt to provide what they think are useful addendums to what Theologians and Philosophers posit, I'm willing to consider their points, but not because they're actually tapping into good or evil with scientific instrumentation. To think that way is, to my mind, a myth. And I disagree with those like Sam Harris who think they can scientifically qualify human morality or definitively specify the nature of good and evil via science.