Tripoli—As members of Libya’s national assembly elected a new Prime Minister, U.S.-trained engineer Mustafa Abushagur, conflicting reports persisted about how Ambassador Christopher Stevens died during the storming by armed militants of the U.S. consulate in Benghazi. Some American and Libyan officials say the attack that led to the death of four diplomats and the wounding of several others was more coordinated than originally thought but they cautioned much still needs to be pieced together.

There were some indications of advanced planning mixed in with opportunism, they say, pointing to the fact that the heavily-armed assailants came well equipped with rocket-propelled grenades and anti-aircraft guns and were able to maintain sustained firefights with Libyan and American security guards at two separate locations—the main consulate compound, a walled-off villa in an upscale district in the city that housed the small temporary mission, and another building a mile away where some staff ran for to escape the attack.

They also managed to disrupt an eight-man rescue team of U.S. security personnel dispatched from Tripoli, who flew in by helicopter and landed at Benghazi airport. They were then ferried by members of a Libyan government force to the annex where staff had sought sanctuary from the four to five hour-gunfight. Captain Fathi al-Obeidi of the Libyan Shield Brigade, a Libyan government force made up of different revolutionary militias, told Reuters: “I really believe that this attack was planned.”

The Benghazi assault involved dozens of gunmen from the Islamist Ansar al-Sharia militia, a brigade of fighters who fought in the rebellion that ousted Gaddafi. Unit leaders have admitted that some of their fighters took part but said in a statement issued late Wednesday that they “were not officially involved and were not ordered to be involved.”

But the brigade leaders praised those who protested at the consulate, saying they were “the best of the best” of Libyans and were to right take to the streets against an amateur-made film, Innocence of Muslims. The movie ridicules the Prophet, and triggered the attack on the consulate and protests outside the U.S. embassy in Cairo a few hours before. Members of the brigade say other militants were involved. According to eyewitnesses, the momentum of the protests came from Ansar al-Sharia fighters, who came flooding out of their headquarters and urged and gathering locals to head to the mission.

Yesterday, The Daily Beast quoted one witness, Benghazi salesman Abdel Nushar, saying, “They said they had to punish the Americans for insulting the Prophet.” Fighters involved in the battle in Benghazi themselves say they stormed the consulate because of anger over the movie, which that day had been condemned by scholars at Cairo’s influential Al-Azhar mosque—that condemnation was picked up quickly by Islamist websites and preachers.

“We still have information to assemble and to sift through,” says an American intelligence official. He declined to be identified for this article. “One of the problems is that those involved—from mission staff to Libyan guards and security—have different recollections, which is not unusual, several are traumatized. You also have to take into account that some Libyan officials are eager to pass the buck and cover for their inadequacies in defending the mission. We also have folks in D.C. who would like to turn this into an Al Qaeda-type conspiracy to make up for the really weak security arrangements set up for that mission. Others feel more comfortable pointing the finger at a bigger conspiracy to account for the loss of a U.S. ambassador—they don’t feel happy thinking that this was a lucky shot.”

But the fact that the Benghazi attack came on the eleventh anniversary of 9/11 has fueled speculation that the assault was thoroughly planned. U.S. congressmen argue that the date can’t be just a coincidence. Michigan Republican Representative Mike Rogers, chairman of the House intelligence committee, has claimed that the attack bore the hallmarks of an Al-Qaeda operation and may have been carried out by an affiliate to mark the anniversary.

Libyan leaders, shocked by the death of the 52-year-old U.S. ambassador, have also hypothesized publicly of a link. Yesterday at a press conference in Tripoli Mohamed Yousef el-Magariaf, the president of Libya’s General National Congress, and the country’s outgoing Prime Minister, Abdurrahim Abdulhafiz El-Keib, shifted from pinning the blame on “remnants of the former regime” to suggesting that the consulate attack was a “despicable act of revenge” for 9/11. In recent weeks Libyan officials when faced with criticism of the rampant lawlessness in the country and the weakness of the central authorities have defensively blamed former Gaddafi officials.

Eugene Rogan, director of the Middle East Center at Britain’s Oxford University, was skeptical of how much advance planning went into the assault. “The State Department is going to have to exhaust every possible cause for the violence that took place. It is an extraordinary thing to have one of your ambassadors murdered in this way. And they will have to get to the bottom of what happened. I think you will find that the spread of anger across the Arab world in response to this recent posting of this very inflammatory and insulting film against Islam is something that they are going to have to address.” He believes the makers of the movie and the posting of the trailer dubbed in Arabic was done to provoke “knowingly and willingly.”

The fact the militant militiamen were competent fighters able to hold their own against reinforcements from the Shield Force and show mobility during a fire-fight may surprise some politicians in Washington, D.C.. But it is the story of Libya now: powerful and battle hardened young fighters with heavy weaponry are the bane of the country and can out-gun and out-match the forces available to the government.

There are more than a hundred militias in Libya currently. Dr. Mahmoud Jibril, a centrist political figure who was the runner-up in yesterday’s vote for the premiership, believes that the biggest mistake of the transitional authorities in the immediate months after the overthrow of Col. Gaddafi was to fail to establish a national army and to start early the disbanding of the militias. “It was a big failure,” he told The Daily Beast several weeks ago.

Noman Benotman of the Quilliam Foundation, a think tank in London that tracks Islamic militants, believes that among the fighters in Benghazi were members of the Omar Abdul Rahman Brigades, a shadowy group that claimed responsibility for a rocket attack in May on the Benghazi headquarters of the International Red Cross and a June bombing of the U.S. consulate there. Some media outlets have described the group as Al Qaeda affiliated but Libyan Salafists insist the group is not affiliated with Al Qaeda just supportive of its aims and methods. British private sector experts based in Benghazi point out that the May and June attacks claimed by the group were not especially successful and struck them as amateurish – the bomb was basically a Molotov cocktail and the first rocket fired at the Red Cross building missed altogether even though the shooter was standing right in front of the building.

Speaking exclusively with The Daily Beast before the Benghazi attack—and ahead of his election last night as the country’s new Prime Minister—Mustafa Abushagur said the biggest challenge in the months ahead would be for the government “to take the weapons off the streets” and to provide “opportunities for young men with guns—get them jobs.” He added: “We have to deal with the military formations and include them in the new Libya. Those young men with guns are part of the solution and I would like to get them involved directly. I’d like to get them together and to sit with the government to form a task force and to ask how we can take this forward. They were prepared to give their lives for the country once, so I am sure they will be willing to put a lot of effort to move the country forward.”