The Senate Intelligence Committee's top Democrat said Sunday his party would pursue more investigations into the Trump administration.

CNN's Jake Tapper on "State of the Union" pressed Sen. Mark Warner, D-Va., with questions raised by Michael Cohen's House Oversight Committee hearing this week, pointing out that the former Trump lawyer testified he had no knowledge of any collusion between Trump's 2016 campaign and agents of the Russian government.

"Well, Jake, there's lots of evidence. The question is, what kind of conclusion we're going to reach. The three pieces of evidence that came out of Cohen's testimony, and let me be first to acknowledge, Mr. Cohen doesn't have a great record of veracity," Warner told Tapper. "Matter of fact, he is going to jail, partially because of lies he made to the Senate Intelligence Committee, although the president doesn't have a good record in telling the truth as well."

"The whole notion of trying to get a Trump Tower project going in Moscow. And I point out the fact, Donald Trump had been trying to build a project in Moscow for over a decade. Suddenly, he becomes a candidate for president and he's got a very lucrative deal on the table. I want to find out why," he added.

Cohen is expected to turn in additional documents from his time working as President Trump's personal attorney to Congress. The Virginia lawmaker speculated what may be included in those documents, including the prospect of obtaining phone records between Trump or his campaign and Russian officials.

"What I do know is that Mr. Cohen is supposed to be turning over additional records that we've been looking for, for some time. And that's a fair question [collusion] to ask once we get a chance to look at those records," Warner said.