Time magazine reported that congressional investigators looking into Russia’s role in the 2016 election are investigating both Breitbart and data analytics firm Cambridge Analytica.

Breitbart, which was formerly headed by current White House chief strategist Stephen Bannon, is reportedly under investigation by the FBI for Russian bots allegedly pushing pro-Trump stories from the website. The website has also repeatedly tried to delegitimize stories of ties between Russia and President Donald Trump. Cambridge Analytica is primarily owned by major Trump donor Robert Mercer. Breitbart and Mercer have a symbiotic relationship; he finances the website, and Breitbart regularly promotes the Mercer family’s interests. Bannon also reportedly had a financial stake in Cambridge Analytica, and Federal Election Commission reports have indicated that millions of dollars allegedly paid by a pro-Trump super PAC to the firm were mysteriously sent to a California address registered to Bannon. The Trump campaign also hired the firm and reportedly paid it millions of dollars at the urging of Mercer’s daughter, Rebekah Mercer.

Time, in a May 18 report titled “Inside Russia’s Social Media War on America,” reported that “congressional investigations are probing not just Russia's role” in the 2016 election, “but whether Moscow had help from the Trump campaign.” The investigators, according to Time, are focusing on “two Trump-linked organizations,” Cambridge Analytica and Breitbart. It added that investigators were specifically “looking at ties between those companies and right-wing web personalities based in Eastern Europe who the U.S. believes are Russian fronts.” From the report:

Russia plays in every social media space. The intelligence officials have found that Moscow's agents bought ads on Facebook to target specific populations with propaganda. “They buy the ads, where it says sponsored by--they do that just as much as anybody else does,” says the senior intelligence official. (A Facebook official says the company has no evidence of that occurring.) The ranking Democrat on the Senate Intelligence Committee, Mark Warner of Virginia, has said he is looking into why, for example, four of the top five Google search results the day the U.S. released a report on the 2016 operation were links to Russia's TV propaganda arm, RT. (Google says it saw no meddling in this case.) Researchers at the University of Southern California, meanwhile, found that nearly 20% of political tweets in 2016 between Sept. 16 and Oct. 21 were generated by bots of unknown origin; investigators are trying to figure out how many were Russian.

As they dig into the viralizing of such stories, congressional investigations are probing not just Russia's role but whether Moscow had help from the Trump campaign. Sources familiar with the investigations say they are probing two Trump-linked organizations: Cambridge Analytica, a data-analytics company hired by the campaign that is partly owned by deep-pocketed Trump backer Robert Mercer; and Breitbart News, the right-wing website formerly run by Trump's top political adviser Stephen Bannon.

The congressional investigators are looking at ties between those companies and right-wing web personalities based in Eastern Europe who the U.S. believes are Russian fronts, a source familiar with the investigations tells TIME. “Nobody can prove it yet,” the source says. In March, McClatchy newspapers reported that FBI counterintelligence investigators were probing whether far-right sites like Breitbart News and Infowars had coordinated with Russian botnets to blitz social media with anti-Clinton stories, mixing fact and fiction when Trump was doing poorly in the campaign.

There are plenty of people who are skeptical of such a conspiracy, if one existed. Cambridge Analytica touts its ability to use algorithms to microtarget voters, but veteran political operatives have found them ineffective political influencers. Ted Cruz first used their methods during the primary, and his staff ended up concluding they had wasted their money. Mercer, Bannon, Breitbart News and the White House did not answer questions about the congressional probes. A spokesperson for Cambridge Analytica says the company has no ties to Russia or individuals acting as fronts for Moscow and that it is unaware of the probe.