(CNN) The new acting attorney general who is expected to have oversight over special counsel Robert Mueller's Russia investigation has expressed deep skepticism of the probe, including calling Mueller's appointment "ridiculous" and "a little fishy."

President Donald Trump announced Matthew Whitaker as acting attorney general on Wednesday after he fired Jeff Sessions.

Whitaker, formerly Sessions' chief of staff, made the comments on the radio in 2017 before his appointment at the Justice Department. In those appearances, he also said the President did not obstruct justice when he allegedly asked then-FBI Director James Comey to drop the investigation into Trump's former national security adviser Michael Flynn.

In other radio comments, Whitaker questioned if the investigation into former Trump campaign chairman Paul Manafort was within the scope of the Mueller investigation, said investigating Trump's finances would be outside the Mueller probe's authority, argued there was a case to be made that Mueller's team committed prosecutorial misconduct if they went outside the bounds of the investigation into Russian election meddling, and said Mueller's probe was taking resources away from other investigations.

Prior to joining the Justice Department, Whitaker served as CNN legal commentator for several months in 2017. A US attorney during the Bush administration, he was executive director of the conservative watchdog group the Foundation for Accountability and Civic Trust. He lost a bid for the Republican Senate nomination in Iowa in 2014 to now-Sen. Joni Ernst.

Here's what Whitaker said in those 2017 radio interviews:

On the appointment of Mueller:

Speaking on the "Rose Unplugged" radio program in August 2017 , Whitaker said the appointment of Mueller was "ridiculous" and it "smells a little fishy."

"For whatever reason, Rod Rosenstein determined that the Department of Justice couldn't handle this in their ordinary course of work, which I think was ridiculous," Whitaker said about the deputy attorney general. "An effort by Jim Comey to get this put in place and have somebody that he's very familiar with in Bob Mueller conducting investigations. So I think it smells a little fishy, but I just hope it doesn't turn into a fishing expedition, because I will be one of them ones jumping up and down making sure the limitations on this investigation continue because that's the way it's supposed to be."

Whitaker added that Rosenstein felt "political pressure" to appoint Mueller, and that he was "certain" the deputy attorney general now regrets it.

On the possibility Trump committed obstruction of justice:

Speaking on "The Sean Hannity Show" in May 2017, Whitaker said even if the President asked Comey not investigate Flynn, it would not rise to the level of obstruction of justice.

"Let's assume that the President asked him to stop investigating Flynn," Whitaker said. "That doesn't rise to the level of obstruction of justice and it doesn't sound to me, based on what's been reported, that Jim Comey, as he sat there, believed that the President was telling him to stop the investigation. As you know in the law and in these types of situations, the words and whatever the president did or didn't say is going to be very important. And, if all he did was make a mere suggestion and not an outright command, I don't think that rises to the level of obstruction of justice."

On the investigation into Manafort:

Speaking on conservative commentator David Webb's radio show in August 2017, Whitaker questioned if investigating Manafort was within the special counsel's scope.

"What we do know is Paul Manafort's finances are being looked at," he said. "They conducted an early morning raid of his house. It sounds like unannounced, which again, you know, I could riff on this all day about why no-knock warrants are a really bad idea. And they're looking at his foreign bank accounts and his tax records. And you know, that I think is a question of, is that within the scope of the letter that Rod Rosenstein wrote to Bob Mueller in setting up the special counsel."

On investigating Trump's finances:

Speaking with Webb, Whitaker added the Mueller investigation would be "invalid" and "fraudulent" if it expanded beyond Russian interference in the 2016 election. Whitaker said it would become a "fishing expedition" that was "very dangerous to the Republic."

"There is a valid argument that if somehow there is not expanded authority sought, that the prosecutor stepped out of the authority and that it's an invalid investigation and the whole basis of the investigation is essentially fraudulent," Whitaker said.

"If they are looking at unrelated to the 2016 election Trump finances, they have crossed the red line and they're outside of the scope of their investigation," he added. "And essentially they are on a fishing expedition which is very dangerous to the republic."

On the Mueller team's "prosecutorial misconduct" and the need to speed up the Mueller investigation:

Speaking with Webb, Whitaker added if the Mueller team didn't handle "bias" or what he considered conflicts of interest, it raised the question of if there was prosecutorial misconduct.

"You could have things like prosecutorial misconduct," said Whitaker. "If they don't handle these conflicts well, especially on the special counsel's team. And that there is a real bias or if they do kind of run away and just start investigating whatever they darn well feel like investigating. I think there is a real risk of not only a legal blowback and cases making its way to the Supreme Court on prosecutorial misconduct or whether or not somebody was supposed to recuse based on conflicts."

"I also think there was an interesting comment yesterday from the President on this investigation and that is why don't these folks hurry up," he said. "I mean it is not helping this administration and really not helping the federal government generally to have the president and his associates under the cloud of a federal investigation. I mean it is. It is very hard."

On the "political" Mueller investigation:

Speaking on Iowa talk radio in August 2017 , Whitaker, comparing the Russia investigation to Ken Starr's investigation into President Bill Clinton, called Mueller's probe "equally political" and said it was taking resources away from other FBI investigations.

"A lot of the resources of the FBI is being focused on the Russian investigation -- even though we still haven't seen any real evidence that there was any coordination between the campaign and the Russian government," he said. "I still continue to believe that investigation, an equally political investigation, is taking a lot of resources away from the FBI where they can focus it on other areas."