Paul Wood at the BBC has made the connection between the probing and successful hack of voter registration databases and interference with the 2016 presidential election. He ties it all together via the "micro-targeting" of voters. He doesn't name the firm, but is most likely referring to a data analytics company that was working for Trump called Cambridge Analytica. Robert Mercer, a major Trump donor was a significant investor in Cambridge Analytica.
Here is a little background on Mercer from a Guardian article by Carole Cadwalladr.
"I recognised Robert Mercer’s name: because of his connection to Cambridge Analytica, a small data analytics company. He is reported to have a $10m stake in the company, which was spun out of a bigger British company called SCL Group. It specialises in “election management strategies” and “messaging and information operations”, refined over 25 years in places like Afghanistan and Pakistan. In military circles this is known as “psyops” – psychological operations. (Mass propaganda that works by acting on people’s emotions.)"
If your interested in micro-targeting - here is more information than you ever dreamed possible about it. It uses "psychometrics" and is part of the "Big Data" narrative.
Back to the Wood article:
"This is a three-headed operation, said one former official, setting out the case, based on the intelligence: Firstly, hackers steal damaging emails from senior Democrats. Secondly, the stories based on this hacked information appear on Twitter and Facebook, posted by thousands of automated "bots", then on Russia's English-language outlets, RT and Sputnik, then right-wing US "news" sites such as Infowars and Breitbart, then Fox and the mainstream media. Thirdly, Russia downloads the online voter rolls.The voter rolls are said to fit into this because of "microtargeting". Using email, Facebook and Twitter, political advertising can be tailored very precisely: individual messaging for individual voters.
"You are stealing the stuff and pushing it back into the US body politic," said the former official, "you know where to target that stuff when you're pushing it back."
This would take co-operation with the Trump campaign, it is claimed.
"If you need to ensure that white women in Pennsylvania don't vote or independents get pissed in Michigan so they stay home: that's voter suppression. You can figure what your target demographics and locations are from the voter rolls. Then you can use that to target your bot."