If you have not seen Hotel Rwanda you should.
If you have not read/seen the play/film The Crucible (Authur Miller) you should.

Both are very moving and personal looks at horrific killing sprees in the recent (the 1994 Rwandan genocide) and more distant (the Salem witch trials) past. What stands out powerfully about each is its dedication to the humanness of its characters. Don Cheadle is heart-breakingly stoic as Paul Rusesabagina - a practical, loving man who becomes the saviour of several hundred Rwandans seemingly, more than anything else, for love of his wife and children;
and John Proctor (played by Daniel Day Lewis in the film), the hero of Authur Miller's play, is so full of a tenuous honor - constantly at war with his overwhelming sense of guilt and inadequacy - that when he finally learns to forgive himself and stand his moral ground only to be sent off to the gallows, it is more triumphant than William Wallace's Hollywood death cry.

What is boggling my mind, after experiencing these two stories in the same week, is that, at any time in history when an opportunity arises (due to a government, movement or social atmosphere) there never seems to be a shortage of human beings ready and willing to carry out all sorts of atrocities against their own kind. Where do these people come from? Are they smoldering in our "peaceful" societies, ready to destroy us all at any moment? Or is some "brainwashing" required before they will become murderers? In the case of the Salem Witch Trials, the perpetrators were "devout" Christians acting, apparently, spontaneously as the social climate gave opportunity.
Sometimes I wonder what prevents our world from going straight to hell.