The FBI is investigating the use of Russian bots that promoted pro-Trump Breitbart stories on social media. Much of the activity occurred during the time Donald Trump surrogate Steve Bannon was in charge of the site.

Breitbart News is reportedly one of the subjects of a federal investigation into Russian interference in the 2016 election, raising the question of the role played by Donald Trump’s senior advisor and campaign chairman Steve Bannon, who led Breitbart for years.

McClatchy reports that investigators are looking into a Russian cyber operation that helped to spread news stories — some of them wholly fake — that were slanted in favor of Trump during the presidential election. The investigation is apparently part of the larger inquiry into Trump and his campaign that has been ongoing since summer of 2016, recently disclosed by FBI director James Comey.

According to McClatchy’s sources, “Operatives for Russia appear to have strategically timed the computer commands, known as ‘bots,’ to blitz social media with links to the pro-Trump stories at times when the billionaire businessman was on the defensive in his race against Democrat Hillary Clinton.”

Automated messages on services like Twitter backed Trump by a 5:1 ratio, accounting for one third of the traffic on the service at its peak.

In addition to Breitbart, the bots spread misinformation from pro-Trump news and propaganda sites like Infowars (whose owner, Alex Jones, is an informal Trump advisor), as well as the outlets RT and Sputnik, both owned and operated by the Russian government.

In November, Breitbart bragged that it had hit a record amount of traffic in the days leading up to the election, with much of that generated by social media accounts.

For much of the campaign, Breitbart’s day to day operations were overseen by Bannon, who took over the site after the death of founder Andrew Breitbart, and operated it until he was hired by Trump. In that time, Bannon said that he had transformed the site into “the platform for the alt-right,” the white supremacist strain of conservatism that Trump has taken under his wing.

Bannon was in charge of the site until August of 2016, when he took over for ousted campaign chairman Paul Manafort (who also has extensive ties to pro-Russian elements). Much of the bot-enhanced traffic that would be under FBI investigation would have occurred while Bannon was steering the site editorially to back Trump, a shift in tone that was noted at the time.

Rachel Cohen, a spokesperson for Sen. Mark Warner (D-VA), the ranking Democratic member of the Senate Intelligence Committee, told McClatchy that the Committee “intends to look actively at ‘fake’ news and the ways that Russian bots and trolls were used to influence the election.”

Breitbart trafficked in anti-Clinton smears, and exerted influence on mainstream media coverage of the election. While it was doing so, Bannon was in control, and this message was amplified by external Russian meddling in the American electoral process. The truth needs to come out.