Sen. Dianne Feinstein revealed Sunday that the Senate’s investigation into Russian interference in the 2016 presidential election includes a potential obstruction of justice case against President Donald Trump.

“I think what we’re beginning to see is the putting together of a case of obstruction of justice,” said Feinstein, the ranking Democrat on the Senate Judiciary Committee, on NBC’s “Meet the Press.”

Feinstein pointed to the indictments and pleas of former Trump advisers that have come as a result of Special Counsel Robert Mueller’s investigation. In late October, former Trump campaign manager Paul Manafort and his partner Rick Gates were indicted on a number of charges. Both former National Security Adviser Michael Flynn and former campaign adviser George Papadopoulos pleaded guilty to lying to the FBI.

Feinstein also cited behavior she has seen from the White House and the president’s dismissal of former FBI Director James Comey earlier this year.

“I see it in the hyper-frenetic attitude of the White House, the comments every day, the continual tweets,” she said. “And I see it most importantly in what happened with the firing of Director Comey, and it is my belief that that is directly because he did not agree to lift the cloud of the Russia investigation. That’s obstruction of justice.”

Obstruction of justice is defined as when someone purposefully disrupts or intervenes with an ongoing investigation. In this case, Feinstein points to Trump’s dismissal of Comey as a cause for alarm.

Along with Mueller’s probe, Feinstein’s committee is one of the Senate groups investigating Russian election interference and whether the Trump campaign colluded with Russia.

Trump has repeatedly said that he does not believe he is personally under investigation relate to the FBI’s Russia probe.

Following Flynn’s plea earlier this week, Trump tweeted on Saturday that he “had to fire General Flynn because he lied to the Vice President and the FBI.”

This explanation shifted from Trump’s original statement on why he fired Flynn, which he said had to do with his communication with Vice President Mike Pence about his contact with Russian officials.

On Sunday, he also tweeted that he had never asked Comey to stop investigating Flynn — another denial of a New York Times report, confirmed by other news outlets, from early this year alleging that he had done so.

The president has repeatedly denied any collusion with his campaign and Russia, as well as reports that he is being investigated for obstruction of justice. In June, a lawyer for the president has challenged reports that Trump was being investigated on those grounds.

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