As the special prosecutor Robert Mueller turns up the heat on Trump and his associates, Republicans are fighting back with increased intensity, not just through Trump lawyer Rudy Giuliani.

Last month, U.S. House Republicans proposed impeaching Rod Rosenstein, who has refused to fire Mueller, but quickly withdrew the proposal in favor of trying to hold him in contempt of Congress, a move widely seen as attempting to lay the groundwork for Trump to fire him.

In addition, Trump’s attacks on the FBI are escalating, raising questions about whether Congress would support an investigation of the FBI itself.

U.S. Rep. Mike Coffman (R-Colorado) backed that position last year, after a FBI phone tap led to the resignation of Trump National Security Adviser Michael Flynn.

Asked if the actions of the FBI needed to be investigated, Coffman said:

Coffman: “You know, I think it should be looked into. And here’s one thing. Did the FBI go through the procedures in place in current law to be able to be able to tap into that phone conversation? Are there other violations of law?

Coffman said at the time that he didn’t have a good feeling about Flynn.

Coffman’s office didn’t return an email seeking to know if he still holds this stance and whether he’d join with Trump and other Republicans in pushing for further investigations of the spy agency as Mueller’s investigation of Trump, which relies in part of FBI material, moves forward.

Coffman, who’s expressed broad support for the Mueller investigation, also said last year that the FBI should not just investigate Trump but also the Obama Administration.