Earlier quoted context omitted.
This is the comment that has been in my head since the news broke, and I feel like we are only at the beginning, like the pause before the first drop of a rollercoaster with the forward looking macro (political and economic tension, broadly speaking). Laws and rules only matter so long as we're all willing to believe they do.
Relevant XKCD https://xkcd.com/1958 I think people skip over this a LOT, but it's the basis for society and was long before we had the means to track down most killers and bring them to any sort of justice. Most people, even when given freedom from consequences and ample opportunities, are not murderers.
I don't necessarily disagree with this completely, but it's also worth noting how easily people seem to go with the status quo, eg criminal gangs, nazism, support of genocides, etc.
I think most people have a bit of killer in them, given the right circumstances.