The top Democrat on the House committee investigating the ever-expanding probe into Russia’s involvement in the 2016 presidential race said Sunday that panel members still have no “definitive” evidence that the Trump campaign was working with Moscow to defeat Democratic rival Hillary Clinton.

The first public indication that Russia might have been directly involved emerged in late summer with the release of hacked emails related to the Clinton campaign and from the Democratic National Committee.

“I don't think we can say anything definitively at this point,” California Rep. Adam Schiff, the ranking Democrat on the House Permanent Select Commitee on Intelligence, told CNN’s “State of the Union.” “We are still at the very early stage of the investigation. The only thing I can say is that it would be irresponsible for us not to get to the bottom of this.”

The U.S. intelligence community concluded several months ago that Russia meddled in the race, in which Trump upset the frontrunning Clinton.

And now, the FBI as well as the House and Senate intelligence committees are investigating the matter, which includes retired Army Lt. Gen. Michael Flynn being fired as Trump’s national security adviser for not disclosing talks with at least one Russian official.

The ordeal has grown to include allegations by Trump that the Obama administration wiretapped his campaign and evidence that Flynn initially failed to disclose roughly $67,000 in speaking fees from companies associated with Russia.

Flynn lawyers have suggested their client will testify on Capitol Hill in exchange for immunity.

Schiff said Sunday that he received the immunity offer with “healthy skepticism,” explaining that such a deal might undermine the Justice Department probe.

Democrats and others say the House investigation has already been undermined by committee Chairman Rep. Devin Nunes and are calling for an independent, bipartisan probe like the so-called 9/11 Commission.

Nunes, R-Calif., went directly to Trump after a secret intelligence briefing instead of first reporting his findings to the committee. He later acknowledged reviewing the reports at the White House.

Nunes has resisted calls to step down. Schiff went to the White House last week to review the same documents that Nunes saw.

Senate Majority Leader Mitch McConnell, R-Ky., told “Fox News Sunday” that he doesn’t see the need for an independent probe.

“It’s just not necessary based on what we know now,” he said. “We have a bipartisan investigation underway. .. We don’t need another investigation. It’s being handled appropriately.”

Trump, who has suggested Flynn did nothing illegal and was a political victim, tweeted this weekend that the Russia-connection story is “fake news” and “The real story turns out to be SURVEILLANCE and LEAKING! Find the leakers.”

The Senate Select Committee on Intelligence purportedly will begin interviewing witnesses this week and wants to speak with Trump's son-in-law and close adviser Jared Kushner.