(CNN)The House Intelligence Committee has concluded its interviews for the investigation into possible collusion between President Donald Trump's campaign operation and Russia, a move that signals the beginning of the end for the panel's Russia probe, according to a source familiar with the matter.
House Intelligence Committee to announce they are done with Russia probe interviews
Rep. Mike Conaway, the Texas Republican leading the Russia investigation, is expected to announce Monday that the committee has concluded its interviews and will now be moving onto writing a final report summarizing its findings.
The decision is expected to be met with sharp criticism from Democrats, who have said there are still scores of witnesses the committee should call, and argue that Republicans have failed to use subpoenas to obtain documents and require witnesses to answer questions that are central to the investigation.
The committee is widely expected to issue two competing reports: one from Republicans that concludes no evidence of collusion was found, and another from Democrats that argues a case for collusion, as well as spells out all the avenues the committee did not investigate.
Monday's expected announcement is likely to further inflame the partisanship that's consumed the House Intelligence Committee for the better part of a year, amid fights over Chairman Devin Nunes' role in the investigation and more recently over competing memos about alleged surveillance abuses at the FBI during the Obama administration.
In another sign of the partisan tensions, the committee's top Democrat, Rep. Adam Schiff of California, had not been told as of midafternoon Monday that Republicans planned to end the witness interview portion of the Russia investigation, according to a Democratic source. Conaway and Schiff do plan to speak on Monday, another source said.
A spokeswoman for Conaway declined comment.
Several Republicans on the panel have been signaling for several weeks now that they're ready for the Russia investigation to wrap up, arguing that Democrats are trying to extend the probe into the campaign season.
"To me, I don't see anything else that's out there that hasn't been explored," Rep. Pete King, a New York Republican, told CNN last week.
But Democrats say the committee has raced through its final interviews, while allowing witnesses to pick and choose which questions they answer.
The committee issued a subpoena to former White House chief strategist Steve Bannon in January, but in his return testimony he still did not answer questions about his time in the White House.
Democrats also sought subpoenas for the committee's last two witnesses, outgoing White House communications director Hope Hicks and former Trump campaign manager Corey Lewandowski, but Republicans did not issue them.
"There are a number of steps that I think any credible investigator would say, 'These need to be done,' and we still hope that they will be," Schiff said following Lewandowski's interview last week.
There are still two committees in the Senate that are investigating Russia's 2016 election meddling: the Senate Intelligence and Judiciary Committees.
Still, only the Senate Intelligence Committee appears to be pushing forward at full speed on its probe, as Senate Judiciary Chairman Chuck Grassley is preparing to release transcripts of the committee's interviews with participants of the June 2016 Trump Tower meeting — a potential sign the committee is done investigating that matter.
The Senate Intelligence Committee is preparing to put out recommendations and hold a hearing on election security this month. Senate Intelligence Chairman Richard Burr has said he's separating out the election security issues for the 2018 primary season while the committee continues to investigate questions about collusion and the 2016 election.
This story has been updated.