Another staffer at the State Department has declined a request from members of Congress to talk about his role in maintaining a private email server used by Hillary Clinton, according to a report late Sunday.

John Bentel, a retired employee at State who managed IT for top officials at the agency, declined requests to be interviewed from both the Senate Judiciary Committee and Senate Homeland Security Committee, according to a letter obtained by Politico.

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The chairmen of both, Sen. Chuck Grassley, R-Iowa, and Sen. Ron Johnson, R-Wis., respectively, are considering methods of compelling his appearance. "We are troubled by your refusal to engage with the committees even after repeated overtures of accommodation," said a letter signed by both. "We would, of course, prefer that you meet with us in a voluntary and informal manner, but we will consider other options if faced with a continuing lack of cooperation."

Bentel's lawyer, Randy Turk, argued that it would be superfluous for Bentel to speak with Congress in light of an interview he already provided to the House Committee on Benghazi last year "about precisely what the committtees' letter states is the subject of their investigation."

"Mr. Bentel ... is understandably not inclined to go through that process again since he has already been questioned at great length about what he knows and what he recalls about that subject," Turk told Senate investigators on Thursday, according to an email exchange obtained by Politico. "It seems to me that what is really fair here would be for you and the committees to respect Mr. Bentel's decision not to be interviewed a second time about the same subjects he has already been interviewed about at great length."

"There has been no change in what we have told you previously on several occasions now, both on the phone and in several emails, in response to your prior requests to interview him," Turk added.

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Bentel is the second staffer at State to decline a request for interview from both committees. The first was Bryan Pagliano, a former IT assistant for Clinton who helped set up her server. However, after accepting a deal for immunity from the Justice Department in exchange for cooperating with its investigation into the server earlier this month, Pagliano has faced renewed demands from members of Congress to cooperate with their investigation.

State has reported that more than 2,000 classified emails passed through the server. A report earlier this month suggested that Clinton personally authored at least 104 of those messages. Clinton has argued the information was not classified at the time she sent or received it, though that is immaterial to whether she violated the law.