They killed murderers.
But some underground group, could have killed them even in the war and it still would not be murder. If my grandparents who hid jews in their home would have had an invasion and would have killed the nazi police, out of defense they would be murderers according to your "logic"?

Or they would be criminals for even hiding jews and therefor if they were executed for that, it was o.k. For they were the criminals for hiding the jews? And my grandparents were not murdered in that situation but receiving their just punishment, for they should have obeyed the law? You probably would have been an NSB-er if you were their neighbour who would have ratted on them. If I reason according to your "logic".

In some cases.....
how about all the murderers of those hundred millions of other people