The House Select Committee on Benghazi was created last year to investigate the Sept. 11, 2012 attacks in Benghazi, Libya, and the role former Secretary of State Hillary Rodham Clinton and others played before and after the violence that claimed the lives of four Americans, including U.S. ambassador Christopher Stevens.

After spending 16 months and nearly $4.4 million on the investigation, the committee headed by Rep. Trey Gowdy (R-SC) is preparing to interrogate Clinton in a highly-anticipated, day-long hearing next month that will likely cap the latest congressional probe of the tragedy.

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Clinton has been dogged for months by the scandal over her use of a personal email server during her four years as secretary of state. Some authorities say that arrangement may have resulted in the improper transmission of classified government information in personal emails.

The setup was uncovered by the Benghazi panel, and Gowdy and other Republicans are certain to spend hours questioning Clinton on her mishandling – and possible destruction—of government-related messages.

The controversy has badly undercut Clinton’s campaign for the 2016 Democratic nomination and prompted many Democrats to question her honesty and integrity, something the select committee’s seven Republicans are certain to try to capitalize on during the hearing.

So much attention has been focused on the email controversy that the GOP’s overarching concerns about the Benghazi attacks have been largely forgotten or ignored.

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This is the ninth congressional investigation into the attacks on the U.S. compound. Previous examinations have explored every facet of the event, from questions regarding embassy security and existing intelligence warnings to the response by the State Department and the military in its aftermath.

At the time of the select committee’s creation, House Speaker John Boehner (R-OH) said Gowdy’s past “as a federal prosecutor and his zeal for the truth make him the ideal person to lead this panel. I know he shares my commitment to get to the bottom of this tragedy and will not tolerate any stonewalling from the Obama administration.”

Democrats argue their initial concerns that the probe would turn into a “witch hunt” aimed a damaging Clinton’s White House bid have come true. They charge the investigation has lasted longer than previous congressional examinations, including the one into the assassination of President John F. Kennedy.

“I think we got sidetracked and it’s become a committee to investigate Hillary Clinton,” said Rep. Elijah Cummings (MD), the select committee’s top Democrat. “We could have probably done more to look at Benghazi if we hadn’t gotten so sidetracked with regard to Secretary Clinton.”

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He said the 12-member panel should have focused more on how to boost security measures at U.S. embassies and diplomatic outposts around the world.

Cummings said he knows the panel is “going to look at Hillary Clinton’s emails” when she appears but predicted that when the select committee’s final report is written there will be no findings about the more outlandish conspiracy theories surrounding the attacks, such as Clinton issuing a “stand-down” order to two military personnel at the compound or approving an illicit weapons program in the country.

“The question becomes whether we have made thing safer for our diplomatic corps and I think we have, in spite of our committee,” he said.

Indeed, State Department spokesman Alec Gerlach said the agency had adopted all 29 security recommendations made by its Accountability Review Board in the wake of the 2012 assault and is “committed to implementing each.”

“We have closed 26 of 29 recommendations, some of which require long-term technical upgrades. The remaining three are in progress,” he added.

Still, the GOP is likely to press Clinton on the question of whether she and her team followed security protocols before and after the assault or did enough after a June email from her chief foreign policy adviser Jake Sullivan warned there was a “credible threat” against a hotel Stevens was staying in at the time.

Republicans no doubt will also ask about the now infamous talking points then-U.S. Ambassador to the United Nations Susan Rice used on Sunday talk shows to deliver the administration’s message on Benghazi.

The talking points fueled questions by the GOP about whether Rice tried to mislead the American public about whether Benghazi was in fact a terrorist attack just weeks before Election Day.

Another topic will be the role of longtime Clinton confidant Sidney Blumenthal, who served as an unofficial adviser and passed along on-the-ground memos from Libya that were authored by retired CIA officer Tyler Drumheller. Drumheller died from complications from pancreatic cancer early last month.

Lastly, select committee members like Rep. Jim Jordan (R-OH) could ask about why the U.S. had a presence in Libya in the first place.

Rep. Adam Schiff (D-CA) guessed Clinton’s appearance next month wouldn’t stop Republicans “obsession” with her, saying the GOP views the probe as “good politics.”

“They’re never going to be satisfied because it’s not about what the committee was supposedly established to do,” according to Cummings, noting that Gowdy has said publicly the panel’s final report may not contain any definitive conclusions about what transpired that fateful day.

On Friday, the three year anniversary of the attacks, Gowdy struck a somber tone.

“Ambassador Chris Stevens and Sean Smith were diplomats we asked to represent us in a foreign land. Tyrone Woods and Glen Doherty were former Navy Seals who continued to serve even after the uniforms were pressed and put away,” he said in a statement.

Gowdy said the panel’s goal has always been to conduct as “straightforward” investigation.

"While much outside attention has been paid to the former Secretary, this investigation has never been about her and never will be. It is about our four fellow Americans murdered three years ago, and ensuring we provide answers for their families and loved ones."