CNN reported Wednesday one of the emails it obtained identified Ansar al-Sharia as claiming responsibility for the attack on its Facebook page and on Twitter.
The collection of emails posed more questions about the initial reaction within the Obama administration about who orchestrated the attack Sept. 11 in which Ambassador to Libya Christopher Stevens and three other diplomatic employees were killed, and the reason behind it.
Fox News, which said it also obtained email communications, said it was told between 300 and 400 security, military and diplomatic officials received these emails in real time as the attack played out. Fox said the emails often include "SBU," which means Sensitive But Unclassified.
The day after the attack, President Barack Obama called the incident an "act of terror." However, White House spokesman Jay Carney subsequently maintained for several days that officials had no evidence to indicate an attack on the consulate was "planned or imminent."
Carney maintained that position Wednesday.
"Throughout this process I and others made very clear that our preliminary assessments are preliminary that an investigation was under way," he said.
Carney went on to note that the group itself had sent mixed messages about its role in the attack.
"This is an open source, unclassified email about a posting on a Facebook site," Carney said. "I would also note that within a few hours the organization itself claimed that it had not been responsible. Neither should be taken as fact. That is why there is an investigation."
The administration said for days following Stevens' death that a U.S.-produced, anti-Muslim video likely fueled a spontaneous demonstration in Benghazi as it had in other cities and countries in the region, which led to the attack.
The administration began saying the attack on the consulate was the work of terrorists on Sept. 19.
The first email about the Benghazi attack, sent at 4:05 p.m. EDT, said about 20 armed people fired shots and "explosions have been heard as well." Stevens and four staff members were in the compound safe haven, it said.
Less than an hour later, another email reported "firing at the U.S. Diplomatic Mission in Benghazi has stopped and the compound has been cleared," and a search was under way for consulate personnel.
The final email's subject line read: "Update 2: Ansar al-Sharia Claims Responsibility for Benghazi Attack."
The email's body read, "Embassy Tripoli reports the group claimed responsibility on Facebook and Twitter and has called for an attack on Embassy Tripoli."
That email was sent about 6:07 p.m. EDT.
Ansar al-Sharia denied the claim made on Facebook during a news conference several days later.
The State Department has declared Ansar al Sharia to be an al-Qaida-affiliated group. Fox News said a member of the group suspected of participating in the attack in Benghazi was arrested and detained in Tunisia.