Why not sue the politicians? They DID take an oath of office, right?
With murder-anyone associated with decision-making or with carrying out policy (or, failing to carry out policy) have to bear responsibility. Don’t they?
Yes, if you can show some dereliction on their part, then you could invalidate their immunity and successfully sue them. However, I think you’ll find that very rarely works in court. There has to be some very clear-cut evidence or the court is going to err on the side of believing the official was acting in good faith.