Democrats have apparently left the idea of Russian collusion behind and are now moving on to investigate all of President Donald Trump's businesses and financial dealings, Rep. Devin Nunes, R-Calif., the ranking member on the House Intelligence Committee, said Monday.

"We've been investigating collusion, obstruction," Rep. Nunes told Fox News' "America's Newsroom." "Clearly they have left that far behind and already written off [special counsel Robert] Mueller. Everybody says Mueller will wrap up this week . . . we don't know if Mueller is really wrapping up or not."

Nunes said he does not understand why he cannot talk publicly about former Trump attorney Michael Cohen's testimony from behind closed doors at last week's Intelligence Committee hearing.

"We held this meeting with Cohen behind closed doors, a man who has no security clearance," Nunes said. "We have no reason to interview Cohen any longer, but if we are, his testimony should be released. The circus you saw on Wednesday essentially is what we did behind closed doors."

Mueller should have wrapped up his investigation over a year ago, Nunes said, because there is "no evidence of collusion," but at this point the probe could end "this week or next month or next year."

Cohen's testimony, during which he said he had never traveled to Prague, points to even further questions about a dossier about Trump that is at the center of the Russia investigation, Nunes said.

In addition, Cohen already has been sentenced to prison, but has not yet reported, and Nunes said he thinks that is because he is being used as a "political prop" by Democrats out to get Trump.