Even as House Republicans mount a vigorous defense of President Donald Trump amid the impeachment inquiry, some are growing uneasy about the role that Trump’s personal lawyer Rudy Giuliani played in carrying out US policy with Ukraine — and say there needs to be more investigation about his efforts.

Several Republicans who sit on the key committees say more needs to be learned about Giuliani’s role, while also revealing new concerns about the continuing revelations that are emerging.

“I worry a lot about non-professionals pursuing diplomacy in the name of” American diplomacy, said Rep. Francis Rooney, a Florida Republican and former US ambassador under George W. Bush when asked about Giuliani. Rooney noted “more things keep coming up in the investigation” and the investigation should look at who “who else was involved.”

“They called Watergate a witch hunt,” Rooney noted.

Another Republican House member, who sits on one of the committees leading the impeachment probe, told CNN: “We have to see what his involvement is.”

Texas Rep. Michael McCaul, who is the top Republican member on the House Foreign Affairs Committee, said of Giuliani when asked if he had concerns: “I know he’s been subpoenaed for documents, and I fully anticipate he’s going to be subpoenaed as a witness. I’m going to reserve judgment until we hear from him.”

Asked if he were unnerved at all about Giuliani’s role, McCaul said, “There’s a lot that we don’t know about.”

But what has come to light had become a source of concern for some Republicans — namely the effort by Giuliani to pressure the Ukrainians to probe the Bidens and his effort to smear the then-US ambassador to Ukraine, Marie Yovanovitch. Added to that was the revealing testimony from a former top Trump Russia adviser, Fiona Hill, who sources say testified that then-national security adviser John Bolton referred to Giuliani as a “hand grenade” who was going to “blow everyone up.”

Still, many Republicans continue to downplay Giulani’s role.

Rep. Scott Perry, who has sat in on the impeachment proceedings, noted that he is a “private citizen” when asked about Giuliani’s efforts.

“When they contacted him, he could say yes or he could say no,” said Perry, a Republican from Pennsylvania.

But some Republican aides say members are growing uneasy with Giuliani’s role and closeness to the President in light of the recent allegations that are piling up against the President’s personal lawyer. It’s not as much about the substance of what is alleged — although members are holding their breath about if more comes to light — but it is about his style: his brashness, his unpredictability and his ability to show up on one cable news show after another without much warning.

Aides say that members are frustrated with the biggest flashpoint is that Giuliani is causing headaches.