On February 16, former FBI Director Robert Mueller, as part of his role as special counsel in the investigation, indicted thirteen Russians and three companies for interfering in the 2016 Presidential Election in favor of Donald Trump’s campaign.

Internet Research Agency—an organization based in St. Petersburg, Russia—a primary focus of the indictment, commenced operations to interfere in 2014. The indictment accused the organization of aiming to undermine the U.S. political system.

Trying to assist both Donald Trump and Democratic candidate Bernie Sanders in the primaries, Russians—as evidence suggests—contacted the staff of the organization to post content on American social media websites. Eventually, Russians bought advertisements on Facebook to promote the “Support Hillary. Save American Muslims” rally among other things.

After the election, the defendants—according to the indictment—organized a pro-Trump rally and an anti-Trump rally, which Vox speculates may have been to cause chaos in the U.S.

One of the defendants is Russian oligarch Yevgeny Prigozhin, “Putin’s chef” and a backer of the Internet Research Agency, who has carried out various tasks for Putin over the years. Prigozhin was penalized in 2016 by the United States Department of the Treasury for providing pecuniary aid to the Russian war effort in Ukraine.

While the indictment suggests Russian interference, it does not accuse any specific members of the Trump campaign.