Harvard Law Professor Alan Dershowitz said in an interview that aired Friday on "Rising" that special counsel Robert Mueller Robert (Bob) MuellerCNN's Toobin warns McCabe is in 'perilous condition' with emboldened Trump CNN anchor rips Trump over Stone while evoking Clinton-Lynch tarmac meeting The Hill's 12:30 Report: New Hampshire fallout MORE's key tactic in the Russia probe has been to use perjury traps on subjects in order to flip them.

"In 55 years of practicing criminal law, I have never heard of a case where somebody was indicted for making a misstatement, then being given an opportunity to correct their misstatement after being shown the evidence, then going back and correcting the misstatement. It's simply unheard of," Dershowitz, a frequent defender of President Trump Donald John TrumpOmar fires back at Trump over rally remarks: 'This is my country' Pelosi: Trump hurrying to fill SCOTUS seat so he can repeal ObamaCare Trump mocks Biden appearance, mask use ahead of first debate MORE on legal issues, told Hill.TV's Buck Sexton.

"It really shows that the Mueller tactic has been to spring perjury traps on people, and to then try to turn them if they can," he continued.

Dershowitz's comments came after Trump's former personal attorney Michael Cohen entered into a plea agreement with Mueller, and pleaded guilty for misstatements he made to Congress while testifying about his contacts with Russians during the 2016 campaign.

Mueller is also investigating Jerome Corsi's and Roger Stone Roger Jason StoneThe agony of justice Our Constitution is under attack by Attorney General William Barr Justice IG investigating Stone sentencing: report MORE's connection to WikiLeaks's release of emails belonging to Hillary Clinton's former campaign chairman, John Podesta, during the 2016 presidential race.

Stone and Corsi have both denied being in contact with WikiLeaks founder Julian Assange.

Corsi said earlier that he rejected an offer for a plea deal from Mueller on a charge of lying to federal investigators, saying that pleading guilty would have meant that he would be agreeing to lie.

"If it is true, if Corsi is correct that he made an honest mistake of fact, then he was shown the email, was given an opportunity to amend it and amended it, and then was indicted, I think that would raise some serious ethical question," Dershowitz said.

Mueller's investigation has led to four guilty pleas from former Trump associates, and he has obtained indictments against more than 20 Russian nationals.

— Julia Manchester