The House Judiciary Committee revealed Monday it is investigating whether President Trump could be impeached for obstruction of justice for allegedly attempting to obstruct the special counsel’s investigation of Russian 2016 presidential election interference.

In arguments before the U.S. Circuit Court of Appeals for the D.C. Circuit, the Judiciary Committee said it needs access to grand jury materials that had been left out of the report special counsel Robert S. Mueller issued earlier this year following a 22-month investigation.

U.S. District Judge Beryl A. Howell ruled the committee is exempt from grand jury secrecy rules and should be allowed to see the materials.

Mueller said he did not find enough evidence to say the Trump campaign had coordinated with Russian efforts to rig the 2016 presidential campaign in Trump’s favor. He said he would not take a position on whether Trump was guilty of obstruction of justice because Justice Department rules precluded him from indicting a sitting president.

Judge Thomas Griffith, who was appointed to the bench by former President George W. Bush, questioned the relevance of the Mueller grand jury materials since the current impeachment investigation is focused on Trump’s dealings with Ukraine.

“Don’t believe everything you read in the press,” House general counsel Douglas Letter told the court, indicating Democrats also are trying to determine whether Trump could be impeached for obstruction.

"Did the President lie? Was the President not truthful in his responses to the Mueller investigation?" Letter asked.

Shortly after he took office, Trump fired FBI Director James Comey, who at the time was investigating whether Trump’s campaign had coordinated with Russian efforts to influence the campaign. Trump initially gave a variety of reasons for Comey’s firing but told former Russian Ambassador to the U.S. Sergey Kislyak and Russian Foreign Minister Sergei Lavrov during an Oval Office meeting that firing Comey had relieved “great pressure” on him, describing Comey as “a real nut job.” That meeting was the day after the May 9 firing.

Testimony at the trial of Trump confidant Roger Stone indicated Trump was keenly interested in what WikiLeaks was going to release following the hacking of Democratic computers. Trump told the Mueller probe he didn’t remember discussing WikiLeaks.