Secretary of State Marco Rubio testified Tuesday in a federal criminal case involving his once-roommate and friend, former Rep. David Rivera, saying during cross-examination that he did not know about Rivera's alleged crimes, CBS News reported. Rivera has been accused of secretly lobbying for the Venezuelan government. Rubio and Rivera had a close relationship in the past. Both are Cuban American immigrants from Miami, and Rivera was with Rubio when he picked out his wife's engagement ring. Rivera stood by Rubio's side as he pushed his political career forward while they both pursued their political ambitions in the Florida House of Representatives. "Rubio described a 2017 meeting with Rivera where he said 'insiders in the regime in Venezuela' had convinced former Venezuelan President Nicolas Maduro to step aside, and Rubio said he had no knowledge that Rivera had allegedly been contracted out by a subsidiary of a Venezuelan state oil company to arrange the meeting," according to CBS News.Rubio described his response to the claims that Maduro was planning to step down. "I was skeptical that it was true," Rubio said. "Because we've had so many other people" attempt to do the same thing with "double dealers who were constantly making these claims."Federal prosecutors allege that Rivera and his codefendant Esther Nuhfer sought to influence the first Trump administration to lower political tensions and tone down sanctions on behalf of Maduro and then-Foreign Minister and now interim Venezuelan president Delcy Rodriguez. Rivera and Nuhfer were indicted in 2022 by a grand jury in the Southern District of Florida for failing to register as a foreign agent and money laundering. "Prosecutors allege that the pair were hired in a $50 million contract in exchange for three months of lobbying work in 2017 on behalf of a U.S.-based subsidiary of a Venezuela state oil company, PDVSA, which operates under the name CITGO," CBS News reported.The indictment revealed that both Rivera and Nuhfer were accused of trying to lobby Rubio, who was at the time a Miami Republican senator, and Kellyanne Conway, former White House advisor, on behalf of the Venezuelan government's high ranking leaders. "The attempts to meet Conway were unsuccessful, prosecutors said, but added that the pair did arrange two meetings with Rubio, who is a longtime friend of Rivera's and had been an outspoken critic of the Maduro regime," according to CBS News.This was the first time in more than 40 years that a current Cabinet member was called as a witness in a federal trial, according to The Washington Post.Rubio was asked what he knew about the alleged $50 million contract between Rivera, Nuhfera and a Venezuela oil subsidiary. "I have no such knowledge other than what is in the press and what is in the indictment," Rubio said.