(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.

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.

Read More