Benghazi timeline: How the probe unfolded

Eric Nordstrom, Diplomatic Security Officer and former US State Department Regional Security Officer in Libya, listens while Gregory Hicks, Foreign Service Officer and former Deputy Chief of Mission/Charge dâ??Affairs in Libya, speaks during a hearing of the House Committee On Oversight and Government Reform on Capitol Hill May 8, 2013 in Washington, DC. The committee held the hearing to investigate the events and response to a 2012 attack on one of the United States's diplomatic compounds in Benghazi, Libya.

As soon as it was revealed that U.S. diplomatic offices in Benghazi, Libya, had been attacked on the Sept. 11, 2012, leaving four Americans -- Ambassador Christopher Stevens, Sean Smith with the U.S. Foreign Service, Glen Doherty and Tyrone S. Woods -- all dead, questions arose over how it could have been allowed to happen.

Obama administration officials initially gave differing explanations, and the ensuing political firestorm over what they knew, and when, is still raging in Washington. In early May, three "whistleblowers" appeared before a congressional committee and gave accounts of the events preceding, during and after the attacks that differed from previous administration responses.

President Obama on Monday forcefully dismissed the ongoing controversy over the talking points that the administration initially crafted to describe the attacks, calling it a politically-motivated "sideshow" that "defies logic."

The following is a timeline of events going back to the day after the attacks on the U.S. outposts in Benghazi.

May 17, 2013: Several Obama administrations who were in key positions during the consulate attack acknowledged to Sharyl Attkisson that a range of mistakes were made both that night and in subsequent messaging to Congress and the public, but they insisted those missteps reflected "incompetence rather than malice or cover up."

The officials spoke to CBS News in a series of interviews and communications under the condition of anonymity so that they could be more frank in their assessments. This is the most sweeping and detailed discussion by key players of what might have been done differently.

"We're portrayed by Republicans as either being lying or idiots," said one Obama administration official who was part of the Benghazi response. "It's actually closer to us being idiots."

Separately, Rep. Darrell Issa subpoenaed retired diplomat Thomas Pickering, who co-chaired the independent review board that investigated the Benghazi attack, to testify in a closed session prior to public hearings.

May 16, 2013: After further review of the emails released by the White House, Major Garrett reported that some of the quotes previously leaked by Republicans on Capitol Hill were wrong.

May 15, 2013: The White House released some 100 pages of internal emails showing how the CIA talking points originally referenced al Qaeda's links to the attack in addition to at assessment that it may have been "spontaneously inspired" by the Cairo protests. After revisions, however, the al Qaeda references were removed.

U.S. intelligence officials told CBS News that the CIA did not want to compromise the FBI investigation by suggesting, even by implication, who might have been involved. Senior U.S. intelligence officials also tell us that they wanted to protect classified information already developed on possible culprits.

May 13, 2013: President Obama dismisses the renewed controversy over the talking points that the administration initially crafted to describe the the Sept. 11, 2012, attack, calling it a politically-motivated "sideshow" that "defies logic."

"The whole issue of talking points, frankly, throughout this process, has been a sideshow," Mr. Obama said in a White House press conference with British Prime Minister David Cameron. "What we have been very clear about throughout was that immediately after this event happened ... nobody understood exactly what was taking place during the course of those few days."

May 12, 2013: Former Defense Secretary Robert Gates appears on "Face the Nation," forcefully defending the Obama administration against charges that it did not do enough to prevent the tragedy in Benghazi. He said some critics of the administration have a "cartoonish impression of military capabilities and military forces."

When Gates was asked whether he thought Hillary Clinton might have been complicit in a coverup of the details surrounding the State Department's handling of the incident, he replied flatly: "No."

On the same show, Thomas Pickering -- the former UN Ambassador who, along with former Joint Chiefs of Staff chairman Adm. Mike Mullen, prepared the Accountability Review Board report on the State Department's handling of the Benghazi attacks -- says he didn't think it was necessary to interview former Secretary of State Hillary Clinton "because in fact we knew where the responsibility rested."

May 11, 2013: CBS News' Sharyl Attkisson reports details of approximately 100 interagency government emails, sent on Sept. 14 and Sept. 15, regarding the content of the talking points on the Benghazi attacks. The talking points were revised numerous times before Rice used them on political talk shows on Sept. 16. While the White House says the changes were merely stylistic, critics argue the changes suggest administration officials tried to spare the State Department political criticism over its response to the attacks.

A U.S. intelligence official familiar with the drafting of the talking points told Margaret Brennan: "The changes don't reflect a turf battle. They were attempts to find the appropriate level of detail for unclassified, preliminary talking points that could be used by members of Congress to address a fluid situation."

"Overall, the changes were made to address intelligence and legal issues. First, the information about individuals linked to al Qaeda was derived from classified sources. Second, when early links are tenuous, it makes sense to be cautious before pointing fingers to avoid setting off a chain of circular and self-reinforcing assumptions and reporting. Finally, it is important to take care not to prejudice a criminal investigation in its early stages."

May 10, 2013: Secretary of State John Kerry suggests the congressional hearings featuring the testimony of the three "whistleblowers" shed little new light on the actual events, referring to the hearings as a, "pure, prolonged, political process that really doesn't tell us anything new about the facts."

A senior administration official tells CBS News' Margaret Brennan that suggestsions State Department officials had helped make final, controversial edits to talking points released to members of Congress regarding the Benghazi attacks -- the same talking points used by Ambassador Susan Rice in her television appearances on Sept. 16, were "just false."

"The minor edits they did make were to clarify that the Benghazi mission was not a consulate. As we have said all along, these points were revised by the CIA," said the official.

May 9, 2013: House Speaker John Boehner, R-Ohio, says GOP attempts to piece together a chronological timeline of what transpired within the administration following the Sept. 11 attacks at the U.S. offices in Libya are far from over, and that more hearings should be expected.

May 8, 2013: In much-anticipated congressional testimony, three U.S. officials who were stationed in Libya during the Sept. 11 terrorist attacks deliver emotional accounts of the events and their aftermath. They renew criticism against the government for allegedly issuing stand-down orders to special forces who they claim could have assisted in the response, arguing that such forces could have mitigated the attack's damage had they been promptly deployed.

Speaking publicly for the first time since the attacks, Mark Thompson, the acting deputy assistant Secretary of State for counterterrorism; Greg Hicks, former deputy chief of mission in Libya; and Eric Nordstrom, former regional security officer in Libya, provided perhaps the most detailed public record of what, from their perspectives, happened on the night of September 11, and what might have been done differently.

Hicks said he recalled telling Ambassador Stevens, "we're under attack" in Benghazi, before being cut off.

May 6, 2013: CBS News' Sharyl Attkisson reports more details from Hicks' private testimony in which he claimed a team of Special Forces prepared to fly from Tripoli to Benghazi during the Sept. 11, 2012, attacks was forbidden from doing so by U.S. Special Operations Command Africa.

Hicks told congressional investigators that if the U.S. had quickly sent a military aircraft over Benghazi, it might have saved American lives. The U.S. Souda Bay Naval Base is an hour's flight from Libya.

Admiral Mike Mullen and Ambassador Tom Pickering issue a joint statement saying: "From the beginning of the ARB process, we had unfettered access to everyone and everything including all the documentation we needed. Our marching orders were to get to the bottom of what happened, and that's what we did."

Former Coordinator for Counterterrorism, Ambassador Daniel Benjamin, refutes criticism that his bureau was out of the loop.

"It has been alleged that the State Department's Counterterrorism Bureau was cut out of the discussion and decision-making in the aftermath of the Benghazi attacks. I ran the bureau then, and I can say now with certainty, as the former Coordinator for Counterterrorism, that this charge is simply untrue. Though I was out of the country on official travel at the time of the attack, I was in frequent contact with the Department. At no time did I feel that the Bureau was in any way being left out of deliberations that it should have been part of."

May 5, 2013: Excerpts of an interview investigators conducted with Gregory Hicks, the no. 2 U.S. diplomatic official in Libya who was in Tripoli during the attack on the U.S. Consulate in Benghazi, are leaked to CBS News.

"I think everybody in the mission thought it was a terrorist attack from the beginning," Hicks told investigators.

"For there to have been a demonstration on Chris Stevens' front door and him not to have reported it is unbelievable," he said. "I never reported a demonstration; I reported an attack on the consulate. Chris - Chris's last report, if you want to say his final report - is, 'Greg, we are under attack.'

"...I've never been as embarrassed in my life, in my career, as on that day" (that Amb. Rice appeared on talk shows calling the attack the result of a demonstration,) Hicks continued in his interview with investigators. "The net impact of what has transpired is, [Rice,] the spokesperson of the most powerful country in the world, has basically said that the president of Libya is either a liar or doesn't know what he's talking about. ....My jaw hit the floor as I watched this."

"I have heard from a friend who had dinner with (Libyan) President Magarif in New York City that he was still angry at Amb. Rice well after the incident," added Hicks.

May 3, 2013: The names of Ambassador Chris Stevens, Sean Smith, Tyrone Woods and Glen Doherty are added to the Memorial Wall in the front hall of the State Department. During a ceremony attended by CIA Director John Brennan, Secretary of State Kerry and Vice President Joe Biden, their names are listed among the fallen.

The FBI released the above three images on May 1, 2013, in their investigation into the attack on the U.S. consulate in Benghazi, Libya.
The FBI released the above three images on May 1, 2013, in their investigation into the attack on the U.S. consulate in Benghazi, Libya.

May 1, 2013: The FBI posted on their website surveillance photos of three men wanted in the investigation into the Benghazi attack. The FBI said the individuals, one of whom appears to be holding a rocket launcher, were on the grounds of the U.S. Special Mission in Libya when it was attacked on September 11, 2012.

April 30, 2013: The attorney for a whistleblower on the Sept. 11, 2012 attacks on the U.S. consulate in Benghazi, Libya, said the Obama administration was impeding efforts to allow her client and other whistleblowers to speak.

April 24, 2013:Following the release of the interim report on Benghazi, a group of House Republicans ask President Obama to publicly release more documents related to the September 2012 attack.