The congressional committee investigating the deadly 2012 attack on the U.S. diplomatic mission in Benghazi, Libya, on Thursday will hear from Hillary Clinton, then the secretary of state and now the top candidate for the Democratic presidential nomination.

Clinton and many of her fellow Democrats have seized on the comments in recent weeks by Republican lawmakers as evidence that the goal of the Benghazi committee in the U.S. House of Representatives was to hurt her front-runner status in the campaign for the November 2016 election.

Clinton's appearance follows months of unflattering reports about her use of a private home email server for her State Department work. The reports emerged in part because of the Benghazi committee's demand last year to see Clinton's official records.

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Trey Gowdy, the committee's Republican chairman and a former federal prosecutor, has been put on the defensive as the most high-profile event in his committee's 17-month existence drew near.

"Shut up" was his advice to Kevin McCarthy, the second most powerful Republican in the House, and others in the party who would draw a link between the committee's work and Clinton's declining favorability in opinion polls.

Gowdy says he is focused on a serious inquiry into the killing of J. Christopher Stevens, the U.S. ambassador to Libya, and three other Americans by suspected Islamist militants who invaded the U.S. mission compound in the war-torn city of Benghazi with guns, grenades and mortars.

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"I'm looking forward to answering questions about the real things when I'm there," Clinton said pointedly in a television interview earlier this month. She voiced disgust at what she said were Republican admissions that "it's a political partisan committee for the sole purpose of going after me."