Special counsel Robert Mueller's investigation has moved "way past collusion," Rep. Jim Himes, D-Conn., insisted Monday, commenting there might even be evidence of "criminal conspiracy" at the highest levels of the Trump administration.

"If collusion is helping each other out, there was lots of helping each other out," Rep. Himes told MSNBC's "Morning Joe." "The question is, was there coordination and quid pro quo? Is Michael Cohen or Roger Stone or anyone else, the president, on record as saying, 'Hey, if we do this, we will get that?' That's when you move from collusion to criminal conspiracy."

That might be "the remaining shoe to drop out of the Mueller investigation," Himes said.

Himes stressed nobody knows what evidence Mueller has, however, but at the same time, he said he expects Mueller might implicate Trump before the investigation ends.

"If, in fact, [there is] a conspiracy on the part of a presidential campaign to conspire to defraud the American people or defraud the government, that, believe me, is the closing act, the fourth movement in that symphony," Himes said. "I don't think it gets revealed around a character like Roger Stone or Michael Cohen."

The FBI took Stone into custody Friday during a raid at his Florida home. He faces charges of obstruction and lying to congressional investigators. He says the charges are politically motivated.

The indictment claims Stone was a link between Trump's 2016 presidential campaign and an unnamed organization matching the description of WikiLeaks.