Mr. Gates and Mr. Manafort met years ago when Mr. Gates was interning at Mr. Manafort’s Washington consulting firm, Black, Manafort, Stone, Kelly. The firm was known for running Republican political campaigns and then lobbying the politicians after they won their elections. In Washington, Mr. Manafort was known for representing dictators and strongmen, such as Ferdinand Marcos of the Philippines. Mr. Manafort also represented the Trump Organization to lobby the Treasury Department regarding casino transaction rules. Mr. Gates would later follow Mr. Manafort to a new firm, Davis Manafort, which worked on the campaign of Viktor F. Yanukovych, the pro-Russia former Ukranian president. This work connected the men with Mr. Deripaska, an aluminum magnate and ally of President Vladimir V. Putin of Russia. Mr. Deripaska has been denied a visa to travel to the United States because of allegations that he is linked to organized crime operations, charges Mr. Deripaska has denied. In 2008, Mr. Gates took over the firm’s duties in Eastern Europe, where he worked on business development and contract negotiations. In 2007, Mr. Gates and his wife sold their home in Richmond, Va., for $700,000 and took out a $1.5 million loan for a house in one of the city’s wealthier neighborhoods, according to public records. That same year Davis Manafort embarked on a new venture — a private equity fund created to buy small companies in Russia and Eastern Europe. Oleg Deripaska was the biggest investor in the fund, called Pericles.