It should be noted - as made clear in the Senate hearings - the determination of Russian-backed twitter networks involves the following:
First, "Russian-linked" twitter accounts were identified as any twitter account which
In other words, any twitter account not only based in Russia but even using Cyrillic (e.g. Ukrainian, Serbian, Belorussian, Bulgarian, Macedonian, etc) is "Russian-linked". This would also include any Russian immigrant living in the US (800,000), Israel (several million), Europe (several million) or any Serb, Belorussian, Ukrainian, Bulgarian, Macedonian or member of the various former nationalities of the USSR who use Russian or Cyrillic with respect to their twitter account - all are "Russian-linked".
If these persons happen to retweet each other's tweets they become a 'Russian-linked twitter network'.
If they also happened to mention anything about the US election or the various candidates thereof, then they become 'members of a Russian-linked twitter network attempting to influence the US election'.
pretty easy to whip up the winds of paranoia..