By Dan Merica and Alan Silverleib, CNN
WASHINGTON (CNN) — Late on the night of last September 11, U.S. Ambassador to Libya Christopher Stevens spoke to his deputy for the final time from the diplomatic compound in Benghazi, Libya.
“Greg, we’re under attack,” Stevens told Gregory Hicks.
Within hours, Stevens and three other Americans were dead, victims of an armed terrorist assault that has since become a political and foreign policy flashpoint in Washington’s partisan wars.
The dramatic narrative recounted by Hicks at a marathon Republican-led House hearing on Wednesday reflected the knowledge of a high-level insider who was in Libya that long night and was deeply involved in trying to react to events.
His efforts to determine the circumstances of the attack and muster help for those under siege in eastern Libya were later praised by his superiors and by President Barack Obama.
The step-by-step account riveted the Republican-led Oversight Committee proceeding that was also marked by sharp partisan exchanges over the merits of continued congressional inquiries over the attack.
Republicans once again accused the Obama administration of trying to cover up the fact that it was a well-orchestrated assault by militants, failing to adequately explain events to the public, and then refusing to cooperate with congressional investigators.
Democrats once again accused Republicans of using tragedy for political gain.
Hicks — praised by Republicans as a “whistleblower” — was joined at the witness table by Eric Nordstrom, a former regional security officer in Libya, and Mark Thompson, the State Department’s acting deputy assistant secretary for counterterrorism.
Our goal “is to get answers, declared committee chairman Rep. Darrell Issa, R-California. “The administration, however, has not been cooperative.”
Committee Republicans continued to go after televised remarks by U.N. Ambassador Susan Rice five days after the attack. In them, she insisted the attack was the result of a spontaneous demonstration over an anti-Islam film that turned violent.
GOP critics believe Rice was shielding Obama at the height of his re-election campaign during which there were times that he trumpeted U.S. successes in combating terrorism, including the death of al Qaeda leader Osama bin Laden.
Administration officials say Rice was using official talking points that relied on the best available information at the time.
Rep. Patrick McHenry, R-North Carolina, asked Hicks if there was any evidence early on that the attack was a protest.
“No, there was none,” Hicks said. “I’m confident Ambassador Stevens would have reported a protest immediately if one appeared on his door.”
Hicks also said an inflammatory anti-Muslim YouTube video initially cited as a cause of the alleged protest was “a non-event in Libya.”
He previously insisted administration officials immediately knew the culprit was al Qaeda.
“I think everybody in the mission thought it was a terrorist attack from the beginning,” Hicks told investigators in interviews before the hearings.
In fact, Hicks said during the hearing that he was told by the Libyan president soon afterward that elements with possible terror links were thought to be behind the assault.
The veteran diplomat said his “jaw dropped” and he was “embarrassed” when Rice said the attack was a response to the YouTube video.
Nordstrom said in written testimony it was “inexplicable” a a followup internal State Department review ignored “the role senior department leadership played before, during, and after” the attack.
In the run-up to the hearing, Issa trickled out testimony from the witnesses in an apparent attempt to build anticipation for the session, one of several that have occurred in Congress focusing on security at the compound and the administration’s response.
Committee Democrats accused Republicans of engaging in a “smear” campaign.
“What we have seen … is a full-scale media campaign that is not designed to investigate what happened in a responsible and bipartisan way but rather a launch of unfounded accusations to smear public officials,” said Maryland Rep. Elijah Cummings, the top Democrat on the panel.
“It will be incredibly disheartening if the only reason that this hearing is being held is to level a partisan attack and try to grab headlines,” said Rep. Matt Cartwright, D-Pennsylvania, in a written statement.
White House Press Secretary Jay Carney also weighed in, telling reporters that the Benghazi attack “is a subject that has from its beginning been subject to attempts to politicize it by Republicans.”
For its part, the State Department also accused House Republicans of playing politics with the tragedy.
“This is not sort of a collaborative process where the committee is working directly with us in trying to establish facts that would help, you know, as we look to keep our people safe overseas in a very complex environment,” State Department spokesman Patrick Ventrell said on Monday.
The State Department flatly rejected GOP accusations it attempted to prevent would-be “whistleblowers” from speaking out.
Wednesday’s hearing is another chapter in what has become an epic back and forth between Democrats and Republicans on Benghazi, partly stemming from Rice’s televised comments. The comments are widely believed to have cost her a likely nomination to succeed Hillary Clinton as secretary of state.
Some congressional Republicans sharply questioned Clinton over the administration’s explanation of events and the state of security at the compound at the time of the attack.
Clinton said she took responsibility for the deaths, declaring that as secretary of state, she was “in charge of the State Department’s 60,000-plus people all over the world.”
In January, Clinton testified for more than five hours before the House and Senate Foreign Relations committees. In her testimony, she acknowledged a “systematic breakdown” on Benghazi and said her department was taking additional steps to increase U.S. security at diplomatic posts.
At one point in the hearing, Clinton barely controlled her anger as she responded to a lawmaker who pressed her on the administration’s post-attack storyline.
Critics have questioned the validity of continued congressional scrutiny, especially Democrats, who say Republicans are only interested in discrediting the administration and hurting Clinton’s chances if she were to run for president in 2016.
CNN’s Dana Bash and Elise Labott contributed to this story.