Manafort and Gates both surrendered to the FBI in Washington. They heard the charges against them read in court on Monday.
Among other charges, the indictment claims the two acted as "unregistered agents" of a Ukrainian political party that had pro-Russian interests, laundered money made in Russia and the Ukraine and failed to report earnings made overseas.
Manafort was a political consultant and lobbyist before he rose to the national stage when he chaired Trump’s run for president for five months.
Gates, on the other hand, was less well known. Who is Gates and why is he included in the indictment? Here’s what we know about him.
Gates met Manafort when the two worked for Manafort’s political consulting firms, Davis Manafort Partners Inc and DMP International.
The indictment said Gates would pass on instructions to the lobbyists from Manafort, who communicated with Viktor Yanukovych, the former Ukrainian president.
According to the New York Times, Gates would also fly to Moscow to meet with Oleg Deripaska, a Russian billionaire, who did business with Manafort.
Gates took over the company's affairs in Eastern Europe two years ago, according to The New York Times.
Gates helped start Pericles, a private equity fund. The fund was set up to buy companies in Russia and Eastern Europe.
Gates was one of the organizers of the Trump’s inauguration.
He joined the political action committee America First Policies in January. It is a PAC that pushes the president’s agenda. He left the PAC in March.
As of two weeks ago, Gates was helping with the closeout of the inauguration committee's campaign account, according to the Associated Press.
According to some, Gates was the man who signed off on Melania Trump’s speech at the RNC, the one that appeared to plagiarize parts of former first lady Michelle Obama’s 2008 Democratic National Convention speech.