As President Trump continues to blast the ongoing probe into Russian interference in the 2016 election and potential ties between his campaign and the Russian government as a "political hoax", former White House attorney Ty Cobb is defending Special Counsel Robert Mueller's investigation, calling the FBI official an "American hero."

"I don't feel the investigation is a witch hunt. I wish it had happened on a quicker timetable. But it didn't. And that's, you know, and that's unfortunate. But at the same time, it's not a real criticism of the special counsel that on the timing because there were a lot of surprises," Cobb told ABC News' "The Investigation" podcast in a wide-ranging interview.

Cobb, who joined the White House counsel's office in July 2017 as a sort of in-house "special counsel" on the matter, announced his retirement in May 2018, telling CBS News' chief White House correspondent Major Garett at the time that working for the president's legal team had meant sacrifices — including putting off orthopedic surgeries and living in something akin to an attic, he said.

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The longtime lead lawyer representing Mr. Trump in matters related to the investigation was instrumental in getting the White House to cooperate with Mueller's team, sharing thousands of documents and making senior officials available for interviews with FBI investigators.

Looking back on his time in the White House counsel's office, Cobb told ABC that he disagreed with criticism of Mueller's probe, specifically the president's current lawyer Rudy Giuliani's approach in "ratcheting up the public's concerns about the investigation and its legitimacy."

"I object to that approach. But it's his choice. He's the President. And it's what — it's what Clinton did to Ken Starr," Cobb explained. Cobb said that in his first few months on the job he was able to prevent Mr. Trump from "going on the attack against Mueller. But after Giuliani joined the legal team the president "felt unleashed."

"He's found this very frustrating. It's particularly frustrated him in foreign affairs. He doesn't like the timing. He, you know, wants this over. But it's never gonna be over. I mean, this is gonna go for — this will go through 2020. And if the president's reelected, it'll go beyond that," Cobb said.

Cobb also said he would not agree with sentiment expressed by another former Trump attorney, John Dowd, who described Mueller's probe as one of the "greatest frauds this country has ever seen."

"I think Bob Mueller's an American hero. I think Bob Mueller's a guy that, you know, even though he came from an, arguably, privileged background, you know, has a backbone of steel. He walked into a firefight in Vietnam to pull out one of his injured colleagues and was appropriately honored for that. I've known him for 30 years as a prosecutor and a friend. And I think the — I think the world of Bob Mueller. He is a very deliberate guy. And he — but he's also a class act. And a very justice oriented person," said Cobb.

Cobb described his role in the White House as an "important" and "fascinating task" that he's "proud" of taking on. He was adamant, however, about the distinction that his "legal obligations" were to the institution of the presidency and not the president personally.

"I'm not embarrassed, you know, for having worked there. And certainly the president, himself, is the White House de facto. So I really did work for him. But my legal obligations are — were to the institution," said Cobb. He called the Trump White House a "challenging environment," describing his first day on the job as chaotic.

"I mean, within the first 15 minutes of my, you know, swearing in, [John] Kelly replaces Reince [Pribeus]. And [Anthony] Scaramucci gets fired. So I was a footnote on day one. And it was you know and it really never let up after that," Cobb recalled.

Speculating on Mueller's final report as the special counsel's office prepares to submit its findings on the Russia probe after two years of investigation in the coming weeks, Cobb said the final assessment would be "shorter rather than longer 'cause it's a pretty specific approach."

He doubted, however, that the probe would yield a "silver bullet" to the Trump presidency, saying he didn't believe the American people would learn anything new from the report.