Legendary journalist Carl Bernstein said Mike Flynn is the key to uncovering the Trump campaign's ties to Russia.
"I think it's obvious that Gen. Flynn is in up to his neck in terms, not just of possible crimes involving his speeches and whether or not he registered as a foreign agent, which he should have and didn't," Bernstein said Wednesday on CNN's "New Day."
The leadership of the House Oversight Committee said Tuesday that classified evidence suggests Flynn may have broken the Constitution's Emoluments clause and other laws by accepting payments from Russia and Turkey and then failing to report those payments.
"He is central to what the FBI believes is a cover-up going on among people close to the president of the United States about what happened with the Trump campaign and Russia," Bernstein said.
He said President Donald Trump and his administration are "impeding" the investigation into possible Russian collusion, but he stopped short of accusing them of obstruction of justice.
"The agents and those at the top of the FBI believe the White House is keeping them from learning what they need to know, and Flynn is central to that," Bernstein said. "Flynn's activities are central, his communications with the president, etc., central, and that's what the White House, Trump, is not allowing to be turned over."
Bernstein expressed confidence that newly confirmed Deputy Attorney General Rod Rosenstein would properly oversee the investigation after Attorney General Jeff Sessions recused himself for his own contacts with Russia during the campaign.
"He is going to see, 'Oh my god, there's a cover-up going on,'" Bernstein said. "The question is, what is Mr. Rosenstein, the deputy attorney general, going to do?"
The president-elect tapped Flynn as his national security adviser in November, and he resigned less than four weeks into the job for lying to Vice President Mike Pence about his conversations with the Russian ambassador about the possibility of easing U.S. sanctions.
A month after leaving the Trump administration, Flynn registered with the Justice Department as a foreign agent for his lobbying work on behalf of Turkish interests during the final weeks of the presidential campaign.
Flynn had served as a key foreign policy adviser during Donald Trump's presidential campaign and was one of the administration's first appointees after the election.
He reportedly offered to testify before FBI and congressional investigators in exchange for immunity from prosecution, but his offer was rejected.