Democratic presidential candidate and former Secretary of State Hillary Clinton waited for the beginning of a hearing before the House Select Committee on Benghazi Oct. 22, 2015. During her testimony, Clinton told the House Select Committee on Benghazi she didn't use emails as a main part of her job. Getty

Update: 4 p.m. EDT -- After six hours of testimony from Hillary Clinton on Thursday, the House Select Committee on Benghazi had tested the patience of both the legislators on the panel and Clinton herself. There was a shouting match between Democrats and Republicans at the end of the first portion of the hearing, and Clinton became particularly emotional at one point while discussing, in detail, the deaths of U.S. Ambassador Chris Stevens and diplomat Sean Smith.

"I imagine I've thought more about this than all of you put together," she said. "I've lost more sleep than all of you put together."

She said that a safe room in the diplomatic compound was not properly equipped for a fire that occurred after the fighters who attacked the site used diesel fuel to light a large fire that produced a lot of smoke, forcing staff and the diplomats to attempt to evacuate and use the safe room.

"The safe room was anything but safe," Clinton said. “Neither Chris Stevens nor Sean Smith died from injuries directly inflicted by the attackers, they both died from smoke inhalation. When we have safe havens, we need to have equipment to enable people that are safe within them to withstand what happened in Benghazi."

She described the attacks and circumstances of the deaths in detail during her hours-long testimony. "Libyans found Ambassador Stevens, and they carried him to the hospital in Benghazi, and Libyan doctors labored nearly two hours to try to resuscitate him, and I mention all of this because I want not just the committee members but any viewers in the public to understand that this was the fog of war that the diplomatic security officers and then later the CIA officers responded with heroism, professionalism as they had been trained to do," she said. "We thought things would be safe once they took refuge in the CIA annex, and as we know even though it was a highly fortified … facility … it turned out also to be a target for the militants.”

Throughout the day, the panel repeatedly asked about security requests that were made by those diplomats at Benghazi and later denied. Clinton noted that the secretary of state is not the person who handles those requests personally and that they are generally handled by security professionals. Republicans wondered, still, why the compound wasn't safe enough from the start.

The shouting match occurred just before the committee broke for lunch. The argument was the result of a series of questions regarding family friend Sidney Blumenthal, whom Republicans described as an unofficial adviser in spite of Clinton's protests, and the emails he sent her about Libya. Clinton answered the questions saying that he was not an adviser and that she had a network of staff and official advisers she relied on to make official decisions. Rep. Elijah Cummings, D-Md., became enraged by the questioning and, in a heated exchange with Rep. Trey Gowdy, R-S.C., demanded that the sealed transcript from Blumenthal's testimony before the committee be released to the public.

Original Story:

U.S. Rep. Trey Gowdy, R-S.C., the chairman of the congressional panel charged with investigating the deadly 2012 attack on the U.S. Consulate in Benghazi, Libya, squared off Thursday morning with former Secretary of State Hillary Clinton during a high-profile hearing on Capitol Hill. Clinton was being questioned about the series of events that resulted in the deaths of four Americans, including the ambassador.

The head of the House Select Committee, which its own Democratic members denounce as partisan, began with a pointed line of questioning seeking "the truth" about the attacks, and Clinton answered with measured responses to justify her decisions as secretary of state. Amid inquiries about adequate security at the compound and the reasoning to deploy personnel to war-torn Libya in the first place, the Democratic presidential candidate found herself facing questions with a familiar theme -- her use of emails during her tenure and whether they reflect poorly on her handling of the Benghazi episode.

"I don’t want you to have a mistaken impression of what I did and how I did it. Most of my work was not conducted on email," Clinton would later say after Rep. Susan Brooks, R-Ind., displayed a stack of emails Clinton sent regarding Libya in 2011 and 2012, the latter being a much smaller pile. Clinton then said the bulk of her business was conducted through direct meetings with aides and government officials to discuss policy and strategy.

The Benghazi investigation has been a major source of contention between Democrats and Republicans from the start. Aside from the emails, which were discovered to be on a private Clinton email server as opposed to State Department servers, Republicans have accused Clinton and her State Department of not providing adequate security to the Benghazi compound. Clinton has repeatedly said the department did everything possible to ensure the safety of American personnel in the region. She said Thursday that the U.S. decision to intervene in the Libyan war in the first place was not a decision made alone, but was the result of repeated pleas from foreign partners like France who requested aid.

"This committee is the first committee to review more than 50,000 pages of documents because we insisted they be produced," Gowdy, who was first elected in 2010, said during his opening remarks, ticking off a number of reasons the hearing was being held, emphasizing the American Benghazi victims. "We owe their families our everlasting respect and gratitude. We owe them -- and each other -- the truth."

There have been seven other congressional investigations -- resulting in nine other reports -- into the Sept. 11, 2012, terror attacks on the diplomatic mission in Benghazi, which resulted in the death of U.S. Ambassador Chris Stevens, American diplomat Sean Smith and two CIA contractors. Both Stevens and Smith died of smoke inhalation after the mission was set on fire. The two contractors died later returning fire during a second attack at the CIA annex where security forces evacuated staff.

The Republicans' Benghazi probe was further discredited when House Majority Leader Kevin McCarthy, R-Calif., who was campaigning to become speaker at the time, indicated that the committee was political and meant to hurt Clinton’s electability.

The emails are a major issue in the hearings, and one that has hurt Clinton’s public image over the last several months. Her use of a private address and server while she was secretary of state was discovered in March. The perceived secrecy surrounding the emails, which the department is now reviewing and has been releasing monthly to the public, has played a part in adversely affecting her presidential aspirations, which at one point was seen as an almost inevitable march to the Democratic nomination.

The Benghazi attacks have become a deeply controversial issue, and Republicans in Congress have accused both President Barack Obama and Clinton of several shortcomings in their response. Some of those accusations include but are not limited to claims that military reinforcements were within range to help out but that the White House told those forces to stand down; that Obama used misleading rhetoric after the event, attempting to downplay the attacks as having “Islamic elements” instead of them being an attack of “terrorism”; and that Clinton’s State Department did not take proper precautions to avoid the attacks in the first place.