Ex-White House lawyer Ty Cobb broke with his former boss Monday, saying he doesn't believe special counsel Robert Mueller’s Russia investigation is a “witch hunt.”

“I don’t think it’s a witch hunt,” Cobb told CNN’s Gloria Borger during CNN’s "Citizen Conference."

Cobb also characterized Mueller as “an American hero in my view” and said that he has respected Mueller for decades.

“He was a very serious prosecutor,” Cobb said. “He and I first met in the mid-'80s when we were prosecuting different places, and I have respected him throughout.”

[Related: Robert Mueller could end Russia probe after midterm elections]

Mueller is investigating Russian interference in the 2016 election and whether the Trump campaign colluded with the Kremlin. He is also examining potential obstruction of justice after President Trump fired former FBI Director James Comey.

Trump routinely rails against the probe, calling it a "witch hunt."

Cobb left his post at the White House earlier this year and was replaced by Emmet Flood, who previously served in the Bill Clinton and George W. Bush administrations.