By CNN's Tim Lister and Paul Cruickshank

The often fiercely political debate over who knew what - and when - about the September 11 assault on the U.S. Consulate in Benghazi has taken another turn with the disclosure of a series of e-mails sent from the State Department on the night of the attack.

But the most explosive of the e-mails - which were released late Tuesday - may have been inaccurate, a "spot report" on a rapidly evolving and highly confusing situation.

The disclosure of the e-mail has given new life to the already fevered debate over when the Obama administration learned that the attack was more than a protest that turned deadly but was the work of terrorists.

The e-mail carried the subject line: "Update 2: Ansar al Sharia Claims Responsibility For Benghazi Attack." The message said: "Embassy Tripoli reports the group has claimed responsibility on Facebook and Twitter and has called for an attack on Embassy Tripoli."

That message was sent to a wide range of federal offices, including the FBI, from the State Department at 6:07 p.m. ET on September 11 - seven minutes into September 12 in Libya. At that time, the attack on the consulate was ongoing, and the subsequent assault on the annex building, in which two more Americans would be killed, had not begun.



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Sen. John McCain, R-Arizona, and two other Republicans in the Senate wrote Wednesday to Obama, saying: "These emails make clear that your Administration knew within two hours of the attack that it was a terrorist act and that Ansar al-Sharia, a Libyan militant group with links to Al-Qaeda, had claimed responsibility for it."

However, an examination of the known Facebook and Twitter accounts of Ansar al-Sharia in Benghazi reveals no such claim of responsibility. Aaron Zelin, a research fellow at the Washington Institute for Near East Policy, tracks dozens of jihadist websites and archives much of what they say. He told CNN he was unaware of any such claim having been posted on the official Facebook page or Twitter feed of Ansar al-Sharia in Benghazi.

Zelin, who said his RSS feed sends him any new statement from the group, provided CNN with a copy of that feed. It shows no Facebook update between September 8 and September 12, when a posting late that afternoon first referenced the attack. Zelin notes that the posting referred to a news conference the group had held earlier that day in Benghazi in which it denied any role in the assault on the consulate, while sympathizing with the attackers.

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Accompanying a posting of the news conference on YouTube, a commentary says that the attack on the consulate was "a wave of rage for Allah and his Prophet, it came from the Muslim youths."

The posting continues: "Ansar al-Sharia brigade did not officially participate as a military body, nor received any orders directed from the brigade."

The group's Twitter feed tells the same story. The account, @anssarelshariea, bears the group's logo and a tweet on September 8 - and then nothing until four days later. And at no point is there a claim of involvement in or responsibility for the attack on the U.S. Consulate compound.

Perhaps the person who reported the claim of responsibility - and the threat against the consulate - was viewing another Ansar al-Sharia site, or one supportive of the group.

In the hours following such incidents, it is not unusual for "spot reports" from agencies and overseas posts to pour in to the State Department. They typically include intercepts, what's picked up on social media, witness accounts and what's being said by local officials. They often contain raw, unfiltered information that is then analyzed for clues, patterns and contradictions.

In the case of the Benghazi attack, there were plenty of contradictions. Such situations are frequently chaotic, with claim and counter-claim by witnesses unsure of what happened when, according to U.S. officials. Building a complete picture without access to first-hand-accounts and little visual evidence can be a major challenge to government experts working from thousands of miles away.

So too have been the attempts to pin down who represents Ansar al-Shariah and their movements on the night of the attack.

Wings of Ansar al-Sharia, which means "partisans" or "supporters of Islamic law," are based not only in Benghazi but in the Libyan town of Derna, east of Benghazi. The group's leaders in Derna are thought to include Abu Sufyan bin Qumu, a former Guantanamo Bay detainee.

A different Ansar al-Sharia is affiliated with al Qaeda in the Arabian Peninsula in Yemen, and budding franchises are said to exist in Tunisia, Morocco and Egypt.

As Zelin wrote last month in Foreign Policy, the groups "lack a unified command structure or even a bandleader like the central al Qaeda command....They are fighting in different lands using different means."

Wherever they may be, members of Ansar al-Shariah are united by a shared outlook, one that is implacably anti-Western and in favor of the imposition of Shariah law across the Muslim world.

The description on the Ansar al-Sharia (Benghazi) Twitter feed proclaims: "The goals of Ansar al-Sharia brigade is to implement the laws of Allah on the land, and reject the human implemented laws and earthly made constitutions. There will be nothing ruling in this country other than the laws of Allah."

Zelin said he believes that the rise of the groups heralds the end of the dominance of global jihad by a single hierarchical organization such as al Qaeda - and returns the state of jihad to the jumble that characterized it during the 1990s.

"One key difference, however, is that jihadi groups are now more ideologically homogenous," Zelin wrote in Foreign Policy.

"In the 1990s, jihadis thought locally and acted locally, while many now talk globally and act locally."

CNN's Pam Benson contributed to this report