Fox News senior judicial analyst Judge Andrew Napolitano on Thursday reacted to an "extraordinary" series of developments in Robert Mueller's investigation, saying the special counsel's "road map" for attempting to prove collusion between the Trump campaign and Russia is coming into focus.

Michael Cohen, President Trump’s former personal attorney, pleaded guilty Thursday to making false statements to Congress about a Trump real estate project in Russia.

This marks the first time Mueller’s team charged Cohen as part of their investigation into Russian meddling and potential collusion. Cohen previously pleaded guilty in New York to violating federal campaign finance laws by arranging hush-money payments to women in 2016 “at the direction” of then-candidate Trump.

Appearing on "America's Newsroom," Napolitano said Cohen's new guilty plea is "the tip of the iceberg," and the rest of the iceberg is in Mueller's office.

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"I assure you -- knowing the way the feds operate -- that Michael Cohen has been extensively debriefed before he brought him into a courtroom to say anything, and they've probably already verified everything that he's given them."

Earlier this week, Mueller's office accused former Trump campaign chairman Paul Manafort of lying and violating his plea agreement. And conservative author Jerome Corsi announced he would reject a deal with investigators that would have required him to plead guilty to perjury.

"We're seeing an extraordinary display of events in a very short period of time, all of which have burst upon us since the midterms," Napolitano said." "And they're beginning to show at least the government's theory, at least Mueller's theory, of a road map -- the road map between Trump Tower and Russians."

As for what these developments mean for the length of the investigation, Napolitano said the Mueller probe could stretch "well into 2019."

Earlier in the show, Alan Dershowitz said the guilty pleas to making false statements points to an overall weakness in Mueller's case.

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