Deputy Attorney General Rod Rosenstein testified Wednesday before the House Judiciary Committee for an oversight hearing.
Rosenstein appointed Robert Mueller as special counsel after President Trump decided to fire FBI Director James Comey in May. Mueller has been overseeing the federal investigation into Russian interference in the 2016 election.
Mr. Trump's former national security adviser, Michael Flynn, recently pleaded guilty to one count of lying to the FBI. The president's former 2016 campaign chairman Paul Manafort and Rick Gates, Manafort's former business associate, were also indicted by a federal grand jury in the investigation into Russian meddling in the U.S. election in October and another Trump campaign aide, George Papadopoulos, pleaded guilty to making false statements to the FBI.