The latest example came Wednesday afternoon, when Nunes issued three subpoenas targeting documents regarding former Obama administration officials in his own probe of unmasking -- without getting sign-offs from the House Democrats. Those subpoenas were issued in the same batch as the first subpoenas from the Russia probe, which had bipartisan support.
Two weeks ago, Nunes took a trip to the CIA headquarters to review intelligence related to Russia as well.
Rep. Adam Schiff, the top Democrat on the panel, said Thursday that Nunes had clearly violated the terms of his recusal and it would be up to House Speaker Paul Ryan to enforce the recusal.
"If the speaker wants to allow this type of thing to go on, that's up to him," Schiff said Monday on MSNBC.
Behind the scenes at the Capitol, a struggle played out between lawmakers on the House Russia investigation in the leadup to the issuing of the first subpoenas, CNN reported last week. Democrats have pushed Nunes to relinquish his power over subpoenas -- the strongest tool they have to use in their investigative toolbox -- and instead hand the power to the new leader of the House Russian probe, Rep. Michael Conaway, R-Texas.
Republicans on the panel, meanwhile, have said that the subpoena power still resides with Nunes.
Asked over the weekend to respond to CNN's report that Nunes was still overseeing the committee's subpoenas, Schiff, one of the people who first called for the California Republican to recuse himself, said it was true, but he wished it were not the case.
"He does. I don't think that he should, given that he has stepped aside or recused himself," Schiff said Sunday on ABC's "This Week." "What I have been urging is that we have a committee vote. That's a procedure that's provided for in our rules. Or that the committee delegate to Mr. Conaway, with advice and consultation with myself. That's similar to what the Senate has done, and that's what I recommend we do here."