The Russians really seem like to most likely there still. It would’ve taken quite a bit of knowhow and resources so the Russians would be one of the few organization with motive and opportunity so at this point it seems highly likely that it was the Russians. It could also be some nation state that wants us to think that they are Russian (which I don’t know who would have motive for this). The only other option would be a corporation or hacker group that is really good and knows enough to be able to (and also have a motive to) implicate the Russians convincingly, but that seems unlikely.

That’s the analysis I heard so it doesn’t really change the overall analysis but I’m no expert and I’m open to other views.