This is questionable ... OK, let’s assume they can show that the hacks came from Russian intel sources ... but there is no way they can actually figure out exactly WHO (what individuals) were on the other side of the keyboards ... or did they just indict a bunch of random Russian intel operators (who will never stand trial) for publicity sake?
... one thing that the CIA (and presumably their Russian counterparts) can do is disguise their hacks to make them look like they’re coming from another source ... this is just murky “Spy vs Spy” stuff and anyone who thinks that Mueller and his team could actually prove a case like this “beyond a reasonable doubt” IF there ever was a trial (which of course they know there never will be) must be smoking something ...