At a surprise news conference on Friday, Deputy Attorney General Rod Rosenstein announced that the Justice Department would be charging 12 Russian intelligence officers with a wide range of offenses, including conspiracies to hack the Democratic National Committee, state election systems and other targets. This brings the total number of the people charged in connection with special counsel Robert Mueller’s investigation into Russian interference in the 2016 election to 32.

It’s a large number considering that the investigation has been active for only 14 months. So far, Mueller has filed charges against five American, one Dutch and 26 Russian nationals, along with three Russian businesses. Of all those indicted, five people have pleaded guilty — including one who has already served prison time — and Paul Manafort, President Trump’s former campaign chairman, is awaiting trial. (The charges against him are related to his lobbying work, not election interference.) Our analysis of special counsel investigations going back to Watergate shows that a majority ended without charges being filed against anyone, while others took years to produce indictments. Mueller is still working quickly compared with past investigations.

This is the second batch of Russians who have been indicted and accused of meddling with the 2016 elections in the U.S.: In February, the Justice Department filed charges against 13 Russian nationals and three Russian companies in connection with a painstaking online campaign to undermine the 2016 election and support the Trump campaign.

Friday’s charges are perhaps most important because they add compelling evidence to the claim that the Russian government engaged in a coordinated effort to hack U.S. servers — a contention that had been disputed by Trump and some of his allies. And although the indictments allege that someone close to the Trump campaign was in “regular contact” with one of the Russian hackers, we still don’t know whether members of the Trump campaign committed a crime by seeking or using the documents stolen by the Russians. The indictment also alleges that the hacked materials were seen as an opportunity for others, including an unnamed candidate for Congress who requested stolen documents about his or her opponent. In his statement, Rosenstein emphasized that the indictment does not, however, suggest that the hacking “affected any election result.”

These indictments are largely symbolic. It will be nearly impossible for Mueller’s team to compel any of the Russians to stand trial in the U.S., and although the indictments could cause trouble if the accused have U.S.-based business dealings, February’s indictments suggest that court appearances by the newly charged people will be unlikely: Of all the Russian people and entities charged in February, only one Russian company has sent a representative to defend itself in a U.S. court.

The timing of Rosenstein’s announcement will likely have consequences, though. Rather than holding specific people accountable for their role in the hacking, the indictments may serve a larger geopolitical purpose: alerting the Russians to the fact that the U.S. government understands the extent of their interference in a major election. Trump, who according to Rosenstein was told about the indictments in advance, will have an opportunity to reinforce that message to Russian President Vladimir Putin’s face next week, when the two leaders meet in Helsinki. Rosenstein certainly gave them plenty to talk about.