Prosecutors from Special Counsel Robert Mueller’s office have reportedly asked former Trump campaign chairman and “cooperating witness” Paul Manafort about Roger Stone, ABC News reports. Stone, a longtime adviser to President Trump, is reportedly a friend and former associate of Manafort. The two men “frequented the same circles of young GOP operatives” in the 1970s and Manafort served as Stone’s campaign manager when he ran for Young Republicans president in 1977. Stone was also an associate at Manafort’s lobbying firm, Black, Manafort, Stone and Kelly. Mueller’s team is reportedly investigating if Stone is connected to Julian Assange or WikiLeaks in relation to Hillary Clinton’s hacked emails obtained by Russian intelligence disguised as hacker “Guccifer 2.0.” Stone told ABC News it “certainly wouldn’t be surprising” if Mueller questioned Manafort about him, adding he and Manafort “have been friends since childhood.” Mueller’s team reportedly questioned “nearly a dozen individuals” about Stone, and some have appeared before a federal grand jury.