Steps After Genocide

Yes, most have the world has realized that genocide is something we should avoid. That it is morally wrong.
Now the problem is what to do after genocide is stopped. When cleaning up the messes of genocide who is held responsible? Do we look at individuals? Or, do we focus on the entire group?
Throughout the history of genocide, it is known that some of those that committed the acts have gotten away. The world has the challenge of deciding who to hold responsible. Is it correct to try individuals that were just taking orders? We can't possibly know if those people had a choice. It might have been their life or follow orders.
Equally difficult is the challenge of holding an entire government or group responsible. Do you focus on the leaders, the masterminds? We have to figure out if they had enough control that they basically brainwashed people. Or, come to the conclusion that their followers decided to act on their own.
Everything does not instantly become easy once genocide is stopped.