Worth reading about the Rwandan genocide if you don't know about it. It was only 30 years ago.
This guy's parents probably either fled the genocide itself, or they fled the repercussions they would have to face for taking part in it / being complicit.
Either way, it's not difficult to imagine how it could lead to a fucked up family, and eventually a child filled with hatred for humans and a taste for brutal violence.
The parents should probably be looked into. May have nothing to do with them, but the child having referred to the genocide before makes you think.