The House committee investigating the deadly Benghazi attacks called in a former top aide to Hillary Rodham Clinton for an interview Thursday, as the panel resumes its review of the 2012 terrorist attack in Libya and Clinton’s use of a private email server while serving as secretary of state.

Meeting behind closed doors, members of the panel were questioning Cheryl Mills, Clinton’s former chief of staff. Jake Sullivan, another former top aide who now works on Clinton’s presidential campaign, was set to be interviewed on Friday. Both sessions will be off limits to the public.

Republican Rep. Trey Gowdy of South Carolina, chairman of the Benghazi committee, said before the interview began that Mills “is no different from any other witnesses” who also have been interviewed in private.

The panel is likely to ask Mills about her role in preparing “talking points” for Obama administration officials following the 2012 attack on U.S. diplomatic facilities in Benghazi, Libya that killed four Americans, including the U.S. ambassador to Libya.

Questions also will focus on Clinton’s use of a private email account and server while she was secretary of state.

The interview with Mills comes as a former State Department employee who helped Clinton set up the private email server said he will assert his Fifth Amendment right not to testify before the Benghazi panel.

Attorneys for Bryan Pagliano sent the committee a letter Monday saying their client would not testify at a hearing planned for next week. The panel subpoenaed Pagliano last month.

Maryland Rep. Elijah Cummings, the top Democrat on the Benghazi panel, said he is not surprised that Pagliano would refuse to testify, given the “wild and unsubstantiated accusations” against Clinton.

The congressional committee was launched last year to investigate the Obama administration’s response to the Benghazi attacks, but the probe has widened in recent months to focus on Clinton’s use of a private email account and server.

Clinton has dismissed both controversies as “partisan games.”

Nick Merrill, a spokesman for Clinton’s campaign, said in a statement Thursday that Clinton and her team “have been confident from the beginning that Hillary Clinton’s use of a personal email was allowed and that she did not send or receive anything marked classified, facts confirmed by the State Department and the inspector general” for the State Department.

Clinton “has made every effort to answer questions and be as helpful as possible, and has encouraged her aides, current and former, to do the same, including Bryan Pagliano,” Merrill said.

Clinton is set to testify before the Benghazi panel next month.

(AP)