Veteran investigative journalist Carl Bernstein said his sources are telling him that Attorney General William Barr is preparing to push a "deep state" conspiracy to protect President Trump.

During an appearance Thursday on CNN, the famed Watergate sleuth reacted to controversy about an intelligence community whistleblower who filed a complaint alleging Trump improperly leveraged military aid to encourage Ukrainian President Volodymyr Zelensky to investigate former Vice President Joe Biden and his son, Hunter.

Trump attacking the whistleblower's sources as being "close to a spy" and alluding to capital punishment, Bernstein said, provided "real time" evidence of the president's corruption. Additionally, Bernstein said the release of the Trump-Zelensky call transcript and the whistleblower's complaint provided proof of "the president’s corruption, of his willingness to undermine the free electoral system in this country, to involve foreign powers in our election and also to try and get involved at the president’s behest there."

The complaint and the notes of the July 25 call, both released to the public this week, show Trump urged Zelensky to speak with his personal attorney Rudy Giuliani and Barr about investigating the matter related to Joe Biden, who is now a leading Democratic candidate for president.

The Justice Department denies Barr ever spoke to Trump about it, and the attorney general has resisted Democratic calls for him to recuse himself from Ukraine-related investigations, but Bernstein insisted that Trump's comments are proof of the attorney general's "connivance" to put out a narrative about sinister forces within the federal government bureaucracy taking aim at Trump.

The Justice Department also received a criminal referral about a potential campaign finance violation in relation to Trump's phone conversation with Zelensky but declined to take action after a review.

Bernstein said Barr is trying to "bring about proof that there is a deep state conspiracy that led to" special counsel Robert Mueller's Russia investigation and suggested that this is a story other journalists are chasing. "Barr is trying to deliver — and I have this, as do other reporters from other sources — to deliver evidence that perhaps this has all been a deep state conspiracy just like Donald Trump alleges," he said.

Bernstein appeared to be referencing the Justice Department's review of the origins of the Russia investigation being led by U.S. Attorney John Durham, examining whether there was any misconduct by Justice Department and FBI officials.

Barr said in May that Mueller did not assess the early stages of the Trump-Russia investigation, which is what he is doing now. "We should be worried about whether government officials abused their power and put their thumb on the scale," he told Fox News.

Democrats have expressed alarm with the DOJ inquiry, particularly after Trump granted Barr broad authority to declassify information related to the federal investigation into possible ties between the Trump campaign and Russia. For instance, House Judiciary Chairman Jerry Nadler called the move part of a "plot to dirty up the intelligence community, to pretend that there's something wrong with the beginning of the Mueller investigation and to persecute and bring into line the intelligence agencies."

Republicans have applauded the DOJ inquiry, touting it as a means to achieve accountability and restore faith in the U.S. law enforcement community.

According to the whistleblower complaint, released by the House Intelligence Committee on Thursday, multiple U.S. officials alleged "senior White House officials had intervened to 'lock down' all records of the phone call" between Trump and Zelensky. This involved moving the records to a separate electronic system "that is otherwise used to store and handle classified information of an especially sensitive nature,” which has prompted Democrats to say this is evidence of a "cover-up."

Asked by CNN's Brooke Baldwin if these could be equated to the Nixon tapes in the Watergate era, as Bernstein said he has received text messages today asking this very question, he declined to provide a direct answer. But he did say these are "clearly documents that the president does not want exposed," and he sees "parallels" to what transpired under the Nixon administration.