Rep, Trey Gowdy (R-SC), Chairman of the House committee investigating the 2012 Benghazi attacks told his Republican friends to "shut up" talking investigation unless they were on the committee. Gowdy appeared on CBS' Face the Nation on Sunday, addressing claims that the committee's real purpose was to damage Hillary Clinton politically, a claim first made by House Majority Leader Kevin McCarthy last week.

"Shut up talking about things that you don't know anything about. And unless you're on the committee, you have no idea what we have done, why we have done it and what new facts we have found."

In addition to McCarthy's remarks, Rep. Richard Hanna (R-N.Y.) and a former GOP committee staffer also suggested the committee was created to hurt Hillary Clinton's candidacy. Gowdy described them as "three people who don't have any idea what they're talking about."

"Four dead Americans is more than enough work for me. She's [Clinton] a witness. She was the secretary of state. You have to talk to her. But we have already talked to 50 people not named Clinton. We're going to talk to another couple of dozen not named Clinton."

Hillary Clinton will testify at a committee hearing later this week. She described the committee as "a partisan arm of the Republican National Committee."

"I already testified about Benghazi. I testified to the best of my ability before the Senate and the House. I don't know that I have very much to add," Clinton said on CNN's "State of the Union" on Sunday. "I will do my best to answer their questions, but I don't really know what their objective is right now."

Rep. Elijah Cummings (D-MD), the ranking Democrat member on the committee, was critical of Gowdy's comments.

"It's interesting that after 17 months, $4.7 million and counting of taxpayer money, that Chairman Gowdy is now saying he has another two dozen witnesses to interview. It's very interesting," Cummings said on "Face the Nation." "I do believe that what he has tried to do — I listened to him very carefully — he's now trying to shift back to where we should have been all along. That is looking at the Benghazi incident. And it's clear to me."