BBC and Reuters both reporting possible links between little known Islamist group Ansal al-Shari and the death of the American ambassador to Lybia, J Christopher Stevens, and three other officials.
BBC notes
Libya's deputy ambassador to London, Ahmad Jibril, named Ansar al-Sharia as the perpetrators.
Reuters article adds that the US has been thinking these attacks were too coincidental and have been investigating the possibility of coordination:
U.S. government officials said the Benghazi attack may have been planned in advance and there were indications that members of a militant faction calling itself Ansar al Sharia - which translates as Supporters of Islamic Law - may have been involved.
"It bears the hallmarks of an organized attack," one U.S. official said. However, some U.S. officials cautioned against assuming that the attacks were deliberately organized to coincide with the September 11 anniversary.
Ansar al-Shari seems to be a relative newcomer to Lybia, around only since uprisings began against Quaddafi.
Although its members are most probably Libyan, and the group emerged from the armed Islamist opposition to Col Muammar Gaddafi, Ansar al-Sharia also has links to foreign groups. Last year, without success, it attempted to set up an Islamic state in the eastern part of the country.
BBC reports that their reporter in Libya received eyewitnesses account from a local Libyan reporter:
According to accounts, a group of people were demonstrating outside the US consulate on Tuesday when they were joined by members of an Islamist group in pickup trucks.
The number of fighters was reported to be anything from as many as 80 to as few as 20.
"The Libyan government provides security to all diplomatic missions in the country but I don't think they were prepared for an attack like this," said Mr Jibril.
A Libyan reporter in Benghazi, Osama al-Fitri, told the BBC World Service he had seen militiamen armed with AK47 assault rifles and 14.5mm anti-aircraft machine guns.
Other eyewitnesses spoke of seeing rocket-propelled grenades.
Graffiti on the bombed US consulate in the Libyan city of Benghazi Messages were daubed on the walls of the consulate in Benghazi
The attackers were keen to hide their identities. Al-Fitri said one threatened to shoot him unless he turned off his camera.
The attackers raised the black flag - a Jihadi symbol - over the US consulate.
According to Libya expert, George Joffe, Ansar al-Sharia is one of several Islamist groups active in Cyrenaica, or eastern Libya.