Putin is ex-KGB. He knows how to run operations like this. If there is anybody in the chain of command who Putin doesn't consider 100 percent reliable they are already dead.
Yep, KGB is forever. He is cold. The odd thing is why use Polonium? That is strange. Why not a gun or a knife or a disappearance. Why the red flag,,did Putin want others to know the murder was a KGB style hit?