Dalrymple, a retired psychiatrist, takes on the subject of evil through the lens of Rwanda. A quote:
The murderers were pleased with their work, they thought of all the corrugated iron roofing, cattle and so forth that they were ‘earning’ by it. They had never been so prosperous as during this period of slaughter and looting. Unaccustomed to eating meat very often (the Tutsi were pastoralists, the Hutu cultivators), they gorged themselves upon it, like hyenas finding an abandoned kill in the bush. Very few were their pauses for thought.
Let us not console ourselves with the thought that these were unsophisticated Africans, without the mental capacity to know better: in short, mere savages. Again, I do not know how much Hatzfeld has edited their words, but his perpetrator interlocutors seem to me more articulate than most of the people with whom I have had to deal in Britain as patients over the last decade and a half. Indeed, their language occasionally becomes poetic: though poetic language in this circumstance is mere euphemism.
A mob effect? Or a "Lord of the Flies" sort of thing? The whole piece is at New English Review