However, surely if he was killed to order, the people responsible would make it far less obvious, and if it was attempted to be covered up - surely it wouldn't be as poorly done as this?
I can see the use of killing someone with a painful, elongated death by polonium poisoning, it's obvious, and makes a statement.
I don't feel the same can be said for making the body of someone appear in a locked bag though - people's reactions are closer to "WTF?" rather than shock.