Former US attorney Preet Bharara
Drew Angerer/Getty Images
Former US attorney Preet Bharara
(CNN) —  

As Robert Mueller’s probe reaches those in President Donald Trump’s inner circle, former US attorney Preet Bharara says he is concerned that the President could interfere in special counsel Robert Mueller’s investigation.

“I would worry in a real way that Donald Trump may preemptively pardon some people, and I still worry in a real way that Donald Trump may decide to cause the firing of Robert Mueller,” Bharara told David Axelrod on “The Axe Files,” a podcast from the University of Chicago Institute of Politics and CNN.

Bharara, a former US attorney in New York who himself was ousted by Trump, said the President has already demonstrated his willingness to exercise his “full constitutional authority” to both pardon and fire people. Bharara noted that fraught political situations, as with the pardon of Sheriff Joe Arpaio and the firing of FBI Director James Comey, do not seem to dissuade Trump from exercising those political powers.

Reacting to former national security adviser Michael Flynn’s guilty plea, which occurred just hours before the “Axe Files” interview, Bharara said there are still a number of questions to be answered. Flynn pleaded guilty on Friday to lying to the FBI about conversations with Russian Ambassador Sergey Kislyak. He is the first person who held a position inside Trump’s administration to be reached by Mueller’s probe.

One of the biggest of those questions, Bharara suggested, was why did Flynn lie to the FBI?

“Federal prosecutors know – and they know the juries understand this – if you’re lying about something, there’s usually some reason for it,” Bharara said. “You’re trying to hide something. You’re trying to protect someone.”

“People might view this as a narrow charge, but given the nature of what the lie was about, given the fact, by the way, this was on the fourth day of the presidency of Donald Trump – he had been the national security adviser for four days on January 24, and he’s a member of the government and he had been a general – and the FBI comes into his office and asks him direct questions and he lies about things that had happened just in recent days. That’s an extraordinary thing,” Bharara said.

He noted that the charges against Flynn, along with those against former Trump campaign aide George Papadopoulos, suggest that Mueller is focusing in on obstruction.

“I will say that it does show a couple of things, combined with the George Papadopoulos plea, that the Mueller team … cares very deeply about issues of lying and issues of obstruction, and to the extent that the special counsel is looking at obstruction on the part of other people, up to and including the President of the United States, this is not a team that takes that lightly,” he said.