Rod Rosenstein, the former deputy attorney general, will testify before the Senate Judiciary Committee next week as part of the Republican-led committee’s review of the origins of the FBI’s investigation into Russian interference in the 2016 election. Rosenstein will be the first witness to testify before the committee on June 3 regarding “information that has come to light concerning the Foreign Intelligence Surveillance Act process and the FBI’s counterintelligence decision-making,” he said in a statement. “Independent law enforcement investigations, judicial review, and congressional oversight are important checks on the discretion of agents and prosecutors.”

Committee Chairman Lindsey Graham (R-SC), one of Trump’s fiercest defenders, said that the committee will vote on June 4 to force former Obama administration officials to testify about the basis for the long-running Russia investigation. Trump has recently been promoting the conspiracy theory that Obama deliberately sabotaged the incoming Trump administration by ordering the Russia investigation in the final days of his presidency.