For pro-Al Qaeda groups trying to establish a stronghold in post-revolutionary Libya, Tuesday provided the perfect storm.

It was Sept. 11.

Al Qaeda’s leader, Ayman al-Zawahiri, released a statement confirming, condemning and calling for revenge for the summer death of the group’s senior Libyan member.

And most fortuitous for armed militants, protests concerning a U.S.-made film offensively depicting Islam’s Prophet Muhammad had reached Benghazi, where demonstrators surrounded the U.S. consulate.

These were some of the reasons intelligence officials and Libyan analysts cited Wednesday in suggesting that the killing of U.S. Ambassador Christopher Stevens and three of his American colleagues was not the work of an angry mob, but a planned assault by an Al Qaeda-inspired organization.

Noman Benotman, president of the London-based Quilliam Foundation and former commander with the Libyan Islamic Fighting Group (LIFG), was the first to note a connection.

“These are acts committed by uncontrollable jihadist groups,” the president of the counter-extremism think tank wrote in a statement early Wednesday.

Citing unnamed Libyan sources, Benotman said the attack was the work of about 20 militants, primed for a military assault. While Libya remains awash with weapons, Benotman claimed it was rare to see a rocket-propelled grenade at what began as a peaceful protest.

Benotman also said the two-stage attack was well co-ordinated and left U.S. officials vulnerable as they fled.

Obama administration officials later suggested a similar narrative, telling the New York Times that while the circumstances of the killings remain unclear, the suspicion was that an organized group took advantage of the protests or had provoked the demonstrations as a cover.

There are a variety of jihadist group operating in Libya, but the “Imprisoned Omar Abdul Rahman Brigades” was cited as a chief suspect since they had targeted the U.S. consulate previously.

The group claimed responsibility for a failed bombing attempt in June, saying it was in retaliation for the death of senior Al Qaeda member Abu Yahya al Libi — the same commander whose killing Zawahiri lamented Tuesday.

Evan Kohlmann, a terrorism analyst with Flashpoint Global Partners, said another group widely discussed in jihadi forums and among intelligence specialists Wednesday was Ansar al Sharia in Benghazi.

“For what it’s worth, Ansar al Sharia said they were not involved,” Kohlmann said. “However, they said the response (to the film) was justified.”

Kohlmann said it was too early for any definitive answers. “Libya can be a pretty violent and crazy place and what ends up happening is you can get rogue factions operating,” he said.

Ray Boisvert, who recently retired from his position as an assistant director with the Canadian Security Intelligence Service, said he was also wary of pointing fingers at specific groups.

“Those names are certainly familiar but I’ve never placed a lot of value in them because these groups can form and dissolve rather quickly,” Boisvert said.

The deaths, Boisvert added, underscore the greater issues facing Libya — a country awash in weapons and militias.

“A number of foreign fighters remain in-country,” Boisvert said. “They are highly radicalized and are infecting or motivating others to act . . . they will continue to look for opportunities to strike against Western targets and symbols.”