(CNN) Yevgeny Prigozhin is a Russian oligarch dubbed "chef" to President Vladimir Putin by the Russian press. In 2002, he served caviar and truffles to President George W. Bush during a summit in St. Petersburg. Before that, he renovated a boat that became the city's most exclusive restaurant.

But his business empire has expanded far beyond the kitchen. US investigators believe it was Prigozhin's company that financed a Russian "troll factory" that used social media to spread fake news during the 2016 US presidential campaign, according to multiple officials briefed on the investigation. One part of the factory had a particularly intriguing name and mission: a "Department of Provocations" dedicated to sowing fake news and social divisions in the West, according to internal company documents obtained by CNN.

Prigozhin is one of the Kremlin's inner circle. His company is believed to be a main backer of the St. Petersburg-based "Internet Research Agency" (IRA), a secretive technology firm, according to US officials and the documents reviewed by CNN. Prigozhin was sanctioned by the US Treasury Department in December of 2016 for providing financial support for Russia's military occupation of Ukraine. Two of his companies, including his catering business, were also sanctioned by Treasury this year.

CNN has examined scores of documents leaked from Prigozhin's companies that show further evidence of his links to the troll factory.

One contract provided IRA with ways to monitor social media and a "system of automized promotion in search engines."

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