My opinion: Anyone who took part in it either knowing it is illegal or even if the person should have known it is illegal considering his/her position.

Same goes for persons that didn't necessarily know about it but acted negligent or ignored standard procedures that are in place to prevent such a thing.

> But in general a CEO should have a duty to ask questions why a certain division seems to be doing well

Could be negligence, I don't know the specifics here. If it was then he has to be held accountable. But his head might roll in the end regardlessly as people always need a scapegoat, no matter if it's his fault or not. Yet when the government takes action it should not do so just to punish a scapegoat, they should punish because the person broke a law. (if the shareholders fire him even though it's not his fault I couldn't care less, it's their investment and they do not have to act rationally if they want to)