The Sept. 11, 2012, attack on the U.S. consulate in Benghazi was a terrorist attack, not just a protest gone wrong. That is how National Counterterrorism Center Director Matthew Olsen classified the Benghazi attack in his testimony before the Senate Homeland Security and Governmental Affairs Committee last week.

“It appears that individuals who are certainly well-armed seized on the opportunity presented,” he said. “What we don’t have at this point is specific intelligence that there was a significant advanced planning or coordination for this attack.”

The ongoing investigation reveals “a number of different individuals” involved in the attack that killed U.S. Ambassador Chris Stevens and three other Americans.

The ongoing investigation reveals “a number of different individuals” involved in the attack that killed U.S. Ambassador Chris Stevens and three other Americans, Olsen said. According to Libya’s former Deputy Interior Minister Wanis al Sharef (fired after the attack), the incident began when a small, lightly armed group gathered outside the consulate. A crowd of protestors joined them, followed by a larger group of attackers armed with grenade launchers and truck-mounted weapons. This second wave was likely responsible for the primary assault and was ultimately the most brazen and lethal.

The attackers formed a perimeter around the consulate, blocking entrances and firing on the building. As American occupants moved to a fallback building, they were hit with mortar fire from a second group of attackers. Because the assault showed a measure of strategy and sophistication, some have concluded (contrary to Olsen’s testimony) that there was necessarily planning for this assault.

“The way these perpetrators acted and moved, and they’re choosing the specific date for this so-called demonstration,” Libyan President Mohamed Yousef El-Magariaf said on CBS’ Face the Nation. “This leaves us with no doubt that this was preplanned.”

Some lawmakers agree, noting the attack seemed to be too well coordinated to have erupted spontaneously. Media reports (quoting unnamed intelligence sources) have also said the Benghazi attack was planned, possibly orchestrated by the Benghazi militant group Ansar al Shariah.

Parts of Libya are dominated by powerful armed militia groups, vestiges of the 2011 revolution that killed Qaddafi (which the United States supported). They outnumber and outgun the Libyan army, and many are hostile to the new Libyan government, as well as American citizens and foreign presences.

“It is certainly conceivable that these groups take advantage of and exploit situations that develop when they develop to protest against or attack either westerners, Americans, western sites or American sites,” said White House spokesman Jay Carney.

The militant animosity against U.S. interests could have inspired former rebels – still armed from the revolution – to capitalize on the protest, launching an assault from amidst an angry mob. A militia group like Ansar al Shariah, which would have honed assault strategies and coordination in battle against Qaddafi’s military, could have made up some or all of the second and more deadly wave of attackers.

Emerging reports in Libya of post-revolution intimidation and killing by militants is fueling a growing public outcry for the groups to disband. This public sentiment spilled into violence in Benghazi on Friday, when protesters and police gathered outside the Ansar al Sharia headquarters. They stormed the compound and set fire to one of the buildings; the militants fled but several were shot and killed.

Among Ansar al Shariah’s leaders is Sufian bin Qumu, who has been implicated in the consulate attack in the flurry of unnamed official sources in media reports. On-the-record government sources have not confirmed (or speculated) on Qumu’s participation, but his possible involvement is particularly provocative because he was a Guantanamo Bay detainee for six years before being transferred to a Libyan prison in 2007 and freed in 2010.

Revolutions throughout North Africa and the Middle East have created fertile ground for democratic ideals and popular rule, but it has also opened the door for violent extremists to acquire arms and followers in lawless areas.

Interestingly, Qumu was the subject of a Wall Street Journal article published in April last year. The story describes how “former” mujahedeen were supporting the armed revolution, naming Abdel Hakim al-Hasady and Qumu as fighters who had been captured in Afghanistan and sent to Guantanamo.

“Our view is starting to change of the U.S.,” Hasady told the Journal. “If we hated the Americans 100 percent, today it is less than 50 percent. They have started to redeem themselves for their past mistakes by helping us to preserve the blood of our children.”

Qumu was “on the front lines” of the revolution and unavailable for comment.

Concurrent with the attack was a wave of protests over an anti-Islamic film produced in the United States. The White House maintains the attack on the consulate was a reaction to the film, but the Benghazi attack may have grown from a different motive.

Olsen testified that the attackers could have ties to al Qaeda or an al Qaeda affiliate, such as al Qaeda in the Islamic Maghreb. Unnamed intelligence sources cited in the Washington Post said the attacks may have been a reprisal for U.S actions in Pakistan. On June 4, a U.S. Predator UAV in Mir Ali, Pakistan, fired on and killed Abu Yahya al Libi, an al Qaeda operations planner. Intelligence sources suggest the consulate attack was encouraged or inspired by al Libi’s brother, Abdul Wahab al-Qaed al-Libi, a militant in Libya. Coincidentally, al Qaeda leader Ayman al Zawahiri formally acknowledged al Libi’s death in a video released on Sept. 11.

The Benghazi attackers and Zawahiri may never have communicated, but the Libyan consulate attack fits within Zawahiri’s strategy for al Qaeda, writes David Ignatius in the Washington Post. For years, Zawahiri has advocated a “global intifada,” calling on jihadists around the world to independently pursue attacks against al Qaeda’s usual Western and apostate enemies. This is a change from the strategy of large-scale, dramatic attacks pursued under Osama bin Laden. Zawahiri’s approach champions individuals and groups acting autonomously, making al Qaeda as an organized central hierarchy less important.

Revolutions throughout North Africa and the Middle East have created fertile ground for democratic ideals and popular rule, but it has also opened the door for violent extremists to acquire arms and followers in lawless areas. Details of the attack will continue to emerge, but one thing is sure. Despite the killing of bin Laden and many al Qaeda leaders, the violent extremist threat to America remains.