Special counsel Robert Mueller will be carefully monitoring Donald Trump’s reaction to the indictments in his investigation into Russian collusion in the election, former U.S. Attorney Preet Bharara said. He hinted to CNN’s Jake Tapper that Trump may cause himself legal trouble if his actions include, for example, bullying behavior toward witnesses.

“I would look for a couple of things ... whether or not Donald Trump has some reaction and talks in a way that could be used against him in the future — because Bob Mueller would do that,” Bharara, who was fired by Trump, said Sunday on “The State of the Union.”

He added that the president could also send “some kind of message to the potential defendant or other witnesses.”

“Is he sending a message of intimidation in some way through himself or his cohorts, suggesting that people should not be talking and people should keep their mouths shut?”

Such actions could presumably be used in an obstruction of justice case against Trump.

Also, whether the president plans to “use his pardon power to get out of legal jeopardy or trouble any allies of his ... that’s something I would watch very, very closely,” Bharara said.

Bharara pointed to Trump’s unfiltered comments on national TV after he fired then-FBI director James Comey.

“He went on television with [NBC’s] Lester Holt and said some things that I think people find incriminating in connection with an obstruction investigation,” Bharara noted. “He said he fired Comey [over] facts related to a Russia investigation.”

Trump has become increasingly shrill in recent comments about Mueller’s investigation as the first indictments in the probe are reported to be unsealed as soon as Monday. Trump insisted last week that it was “commonly agreed” that Clinton, not him, “colluded with the Russians,” though it is Trump’s campaign that has been the focus of Mueller’s investigation.

Trump released a flurry of tweets Sunday calling Mueller’s investigation a “witch hunt.” He has said repeatedly that the Democrats and Clinton are guilty of colluding with the Russians, pleading: “DO SOMETHING!”

...are now fighting back like never before. There is so much GUILT by Democrats/Clinton, and now the facts are pouring out. DO SOMETHING! — Donald J. Trump (@realDonaldTrump) October 29, 2017

As the Russian probe heats up, Trump supporters are pressing Mueller to resign.

“What a coincidence,” Bharara told Tapper. “As Bob Mueller’s getting his job done and as he’s getting closer to doing something that’s real and filing charges, political allies of the president are calling for his resignation.”

CORRECTION: A previous version of this story indicated Trump had fired Comey last year. Trump fired him in May of this year.