It is also critical of top officials' deliberations during the attacks and the lack of troop mobilization as it unfolded.
In one detail revealed in the report, a U.S. military unit mobilized after the attacks changed in and out of their uniforms and civilian clothes four times. The report also concluded that none of the military forces mobilized met required deployment timelines.
Clinton had planned an October 2012 visit to Libya, plans that were canceled after the Sept. 11, 2012, attack, according to an email obtained by the committee.
Eighty new witness accounts, including nine eyewitnesses never interviewed before, are included in this final congressional report on Benghazi. In all, the committee logged over 16,000 pages of transcripts.
The report rebuts some findings of the previous investigations and focuses on the administration's initially blaming the attacks on an anti-Muslim video posted on YouTube.
The report described how officials, including Clinton, focused on the video in a high-level meeting the evening of the attacks.
Republicans on the committee leaked portions of their report to selected media outlets (not including ABC News) before making the report public and never gave Democrats on the committee a chance to review it.
"There is a reason Republicans leaked pieces of their report in the middle of the night and continue to hide it from Democrats even now. They don't want us to fact-check it against the evidence we obtained," a Democratic spokesman for the committee said early today. "Based on press reports, the Republican Benghazi report seems like a conspiracy theory on steroids, bringing back long-debunked allegations with no credible evidence whatsoever."
Brian Fallon, a Clinton spokesman, blasted the committee on Twitter after the report's release, calling it a "partisan sham."
The select committee, formed just over two years ago, is the eighth congressional committee to investigate the attacks. Its investigation is the 12th on Benghazi.
The panel has attracted partisan controversy since its formation. It was approved in a vote nearly along party lines in the House in May 2014.
It is credited with uncovering Clinton's use of a private email server as secretary of state, which was discovered as the committee looked into correspondence between Clinton and her team after the Benghazi attacks.
Democrats — who have long criticized the two-year, $7 million investigation (the cost of which they contributed to) — have accused Republicans of using the panel to target Clinton because of her White House run, seizing on comments made by House Majority Leader Kevin McCarthy, R-Calif., last fall as he considered a run for House speaker.
"Everybody thought Hillary Clinton was unbeatable, right? But we put together a Benghazi special committee, a select committee," he said in a Fox News interview — comments he later walked back. "What are her numbers today? Her numbers are dropping. Why? Because she's untrustable."
After McCarthy's comments, Committee Chairman Rep. Trey Gowdy, R-S.C., said in an interview with CBS that he told Republican colleagues and friends to "shut up" about the investigation. In the panel's 11-hour interview of Clinton, he told her that the investigation was not about her but about the four American victims of the attacks.
"We cannot say whether the military could have saved lives in Benghazi. We can say with certainty that our nation's leaders did not move heaven and earth to send military help with the urgency that those Americans deserved. We will never know if a more vigorous, comprehensive and urgent response could have saved lives," their appendix reads.
Previous investigations into the attacks determined that the military did all it could that night, given the constraints of time and distance.
The Democrats' report found that administration officials did not "make intentionally misleading statements" about the origins of the attacks but were relying on information provided under "fast-moving circumstances."
The Democratic report also determined that Clinton did not personally deny requests for additional security in Libya before the attacks.