Since a deadly Sept. 11, 2012 attack by militants who overran America's modest outpost in Benghazi, Libya, which resulted in the death of a U.S. ambassador, al Qaeda's role has been hotly debated even as a new threat rises.
The arguments have been made mostly without the benefit of knowing what sensitive intelligence, which remained classified until this week, had revealed about the diversity of the terrorist perpetrators, much less the importance of understanding the larger threat they may portend.
What is no longer debatable is the body of evidence in intelligence channels that groups directly linked to core-al Qaeda in Pakistan have been coordinating operations with each other across North Africa and that the Benghazi attack is Exhibit A, according to ABC News intelligence sources and government reports.
"Individuals affiliated with terrorist groups, including AQIM, Ansar al-Sharia, AQAP, and the Mohammad Jamal Network, participated in the September 11, 2012, attacks," an unusual bipartisan report released this week by the Senate Select Committee on Intelligence revealed for the first time. Two different branches of Ansar al-Sharia, both based in Libya, are accused of being involved in the Benghazi assault.
That intelligence -- known for at least a year by the U.S. counter-terrorism community -- was seen as significant because it meant that these regional al Qaeda affiliates work together better than was believed before Benghazi.
All five groups have been designated over the years as Foreign Terrorist Organizations by the United States and by the United Nations, with the Ansar al-Shariah branches in Libya winning their designations most recently -- this year.
Three of those groups, Al Qaeda in the Arabian Peninsula in Yemen and the Jamal Network in Egypt, and Ansar al-Sharia of Derna, Libya, are commanded by jihadis with longstanding personal ties to the al Qaeda group in Pakistan now led by Egyptian pediatrician Ayman al-Zawahiri since bin Laden's 2011 killing by American commandos.
More than a year ago U.S. intelligence discovered that Algeria's al Qaeda in the Lands of the Islamic Maghreb (AQIM) -- which has, according to a senior U.S. official, an estimated $60-90 million war chest from ransoms, narcotics smuggling and other illicit operations -- was bankrolling and communicating at unprecedented levels with other African terror groups that follow al Qaeda's Salafist ideology.
Besides AQAP and Ansar, Somalia's al Qaeda-core franchise al-Shabaab and Nigeria's upstart jihadi groups Boko Haram and Ansaru have been in the funding and communications loop too, according to ABC News intelligence sources.
"We have seen clear indications of collaboration among these organizations," Army Gen. Carter Ham, who commanded U.S. Africa Command when Benghazi occurred, said at a Homeland Security Policy Institute forum three months after the U.S. Mission and CIA "annex" attacks in 2012.
While protests over a YouTube video that offended many Muslims grew violent on the day of the 9/11 anniversary outside U.S. embassies in Egypt and Tunisia, the attack in Libya began well after nightfall, at 9:40 p.m. local time, which is an unusual hour to be staging a political demonstration.
What really happened, according to the new Senate investigative report, is that terrorists from the five distinct extremist organizations beholden to al Qaeda -- the one founded by Osama bin Laden -- converged in "short order" on the lightly guarded U.S. outpost, penetrated it and set buildings on fire with diesel they found there.
They had organized themselves quickly and efficiently, and they succeeded in overrunning America's diplomatic outpost in the city -- precisely the kind of attack that al Qaeda-core has perfected and is known to teach its allies how to execute.
Last October, the CBS News program "60 Minutes" aired a controverial report in which it said "al Qaeda" was involved, without delineating who they meant. Critics pounced when correspondent Lara Logan told viewers, "Contrary to the White House's public statements, which were still being made a full week later, it's now well established that the Americans were attacked by al Qaeda in a well-planned assault."
The bipartisan Senate report this week said it was "not a highly coordinated plot, but was opportunistic."
It was also, of course, highly successful.
The Obama administration, however, has avoided disclosing specifics on the perpetrators.
Responding to a New York Times story last month that claimed al Qaeda was not behind the worst diplomatic loss the U.S. had suffered in decades, State Department spokeswoman Marie Harf told reporters that "extremists were involved," but without specifying who they were.
"At this point, we have no indications that core-al Qaeda, which I think is what most people are referring to when they talk about, quote, al Qaeda, directed or planned what happened in Benghazi," Harf said on Dec. 30, 2013. "These folks don't carry ID cards. They don't come out and wear a t-shirt that says, 'I belong to al Qaeda,' right? We know some of them may have taken inspiration from al Qaeda ideology, certainly."
Harf would know. She is a seasoned former career CIA terrorism analyst and spokeswoman for the spy agency.
The Senate report did not contradict Harf, but was much more specific.
While a Zawahiri message was released by core-al Qaeda on Sept. 10, 2012 as a eulogy to his Libyan No. 3 lieutenant killed by a CIA drone, Abu Yahya al-Libi, there is no evidence the video or any other direction to attack Stevens' compound in Benghazi came from the leadership in Pakistan or anywhere else.
But they didn't need to. Public statements by bin Laden and Zawahiri showed that al Qaeda's plan for the group bin Laden named "The Base," or "Foundation" 25 years ago was that they would facilitate the spread of violent jihad to be carried out by others.
AQAP is considered by the U.S. to be more lethal than the decimated core-al Qaeda in Pakistan. From Yemen it has launched four unsuccessful airborne attacks against the U.S. homeland using bombs hidden in underwear and printer cartridges aboard planes. The group is led by Nasir al-Wahishi.
"Al-Wahishi has direct ties to al Qaeda and its senior leadership, having been a secretary to Osama Bin Laden (deceased), to whom he has sworn allegiance," according to the UN's designation.
Last October, a year after Benghazi, the Jamal Network was designated as an Foreign Terrorist Organization by the United States, but the group's role in killing Stevens and the others was not disclosed then. The UN, however, noted its leader's bomb training by al Qaeda in Afghanistan in the late 1980s and his membership in Egyptian Islamic Jihad, headed by Zawahiri before merging with al Qaeda formally in 1998.
"MJN members were reported to be involved in the attack on the United States Mission in Benghazi, Libya, on 11 Sep. 2012," the UN said.
AQIM, which targeted American and other western oil and gas workers at a BP site in Algeria by one of its offshoots in a raid a year ago, was formed in 1998 and in 2006 pledged bayat -- fealty -- to Bin Laden and adopted the al Qaeda brand name with Zawahiri's videotaped blessing.
The leader of one of the two Ansar al-Sharia groups in Libya designated by the U.S. this month is Sufian bin Qumu, a former Guantanamo Bay inmate who also trained with al Qaeda in Afghanistan.
Nearly a year and a half after the attack on the Benghazi compound, when asked about al Qaeda's role on Wednesday, Harf reiterated past statements.
"We still have no indications that core-al Qaeda was involved in directly planning this attack," she told reporters.