WASHINGTON: A day after questioning a former top aide to presidential candidate Hillary Rodham Clinton behind closed doors, the House committee investigating the deadly Benghazi attacks expects to question another member of Clinton’s inner circle in closed session.

Jake Sullivan, a former policy director and deputy chief of staff at the State Department, will be questioned Friday in what is expected to be a daylong session.

The panel interviewed Cheryl Mills, Clinton’s former chief of staff, for 9½ hours on Thursday. Few details were released, but knowledgeable officials said the panel asked Mills about her role in preparing “talking points” for administration officials following the 2012 attack on US diplomatic facilities in Benghazi that killed four Americans, including the US ambassador to Libya.

Questions also focused on a private e-mail server Clinton used while serving as secretary of state and how it was set up.

Mills, a lawyer who has worked for former President Bill Clinton, said after the meeting that she was treated with professional courtesy and respect.

Republican Rep. Trey Gowdy, the committee chairman, described the meeting with Mills as professional and productive. Gowdy said the session would be treated as classified and declined to answer any specific questions.

Maryland Rep. Elijah Cummings, the senior Democrat on the committee, called for Gowdy and committee Republicans to release a transcript of Mills’ testimony as soon as possible, so the public can learn what questions were asked and how they were answered. Mills answered all the committees questions, Gowdy said.

The request to release the transcript was unlikely to be granted, Gowdy said, noting that much of what was discussed related to national security.

The interviews with Mills and Sullivan have been upstaged by a lesser-known character in the Benghazi saga, a former State Department employee who helped set up Clinton’s private e-mail server.

The former staffer, Bryan Pagliano, told the committee earlier this week that he will assert his constitutional right not to testify at a meeting set for next week.

Pagliano was a State Department employee from 2009 to 2013 and is now a private contractor working in the department’s Bureau of Information Resource Management, according to a department official who asked not to be identified when discussing personnel matters.

Clinton, the Democratic front-runner for the 2016 nomination, has been dogged by criticism about her use of a private e-mail server for government business during her tenure as secretary of state, and she has struggled to explain her decision.

Pagliano’s response to a committee subpoena was unwelcome news to Clinton aides who had pressed him to be interviewed by the Republican-led panel.

Cummings said he was not surprised that Pagliano would refuse to testify, given the “wild and unsubstantiated accusations” against Clinton.

“This investigation has turned into a (quest to) derail Hillary Clinton’s nomination by any means necessary,” Cummings said.

The special committee was established last year to investigate the Obama administration’s response to the Benghazi attacks, then widened in recent months to focus on Clinton’s private e-mail account and server.

Clinton has dismissed both controversies as “partisan games.” She also has said she regrets using a personal e-mail account to conduct government business.