I don't know. Since it happened Lavrov has stated he will present conclusive proof that the Americans did it, that the UK did it, that the Norwegians did it, that the US and UK did one side each, that the Anglo-Saxons did it, that everyone other than Russia did it. He was so confident that he gave specific dates on when each of these proofs would be presented. Dates that have long since passed. That's good enough for many though.