It was reported earlier this week that Robert Mueller is investigating the U.S. president for obstruction of justice after he reportedly asked then-FBI director James Comey to drop the investigation of Michael Flynn. The special counsel was commissioned to oversee the investigation of Russian interference after Donald Trump fired Comey in May.

'Comey is a leaker!'

The administration cited that they fired the FBI director over his handling of Hillary Clinton's case involving the use of a private e-mail server when she was still Secretary of State.

Trump said the move was meant to restore "public trust and confidence" in the bureau. The Washington Post reported that the U.S. president has said that Comey assured him that he is not under investigation in terms of Russian collusion

The former FBI head, however, denied this claim, and revealed that the president asked for him to pledge his loyalty during their private meetings. Trump fired back and insisted that he would not ask such a thing from a guy he barely knew. The American leader also slammed Comey for disclosing his memos to the press.

Why Mueller?

The Department of Justice appointed Mueller to take over the investigation of Russia's alleged involvement in the 2016 election. A report from NYT stated that the decision to commission a special counsel came after the president's private meetings with Comey came to light.

By having Mueller on board for the Russian probe, Rod J. Rosenstein is hopeful that his leadership will restore the bureau's reputation. A few days after Mueller was appointed, several sources revealed that the special counsel has been doing some extra work by investigating Trump's decision to fire Comey. This was confirmed by the president himself in a series of tweets on Friday morning.

An insider told CNN that the U.S. leader was referring to news reports stating that he is under investigation over Comey's dismissal from the bureau. It added that the president was not personally notified that he would be probed for obstruction of justice.

But, after the news came out, there was speculation that Trump could be planning to fire Mueller from his post as special counsel. This unconfirmed news is already raising concerns among the Dems. In fact, Sen. Dick Durbin said firing the special counsel would cause a "constitutional crisis," according to CNN.

Sen. Dianne Feinstein also expressed her concern over Trump's remarks on social media, which she said appeared like the president "believes the rule of law doesn’t apply to him." The member of the Democratic Party even called the leader's behavior a "violation" of his oath as the U.S. president.