A report on CNN questions the veracity of the email mentioning the Facebook post. Aaron Zelin, a research fellow at the Washington Institute for Near East Policy who tracks dozens of jihadist websites 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, says that there is no Facebook update between September 8 and September 12, when a posting late that afternoon first referenced the attack, in which the group denied Ansar al-Sharia’s role in the assault on the consulate, while sympathizing with the attackers.
The group’s Twitter feed (@anssarelshariea), also has no posts from September 8 – 13 and then nothing until four days later. There is no claim of involvement in or responsibility for the attack on the U.S. Consulate compound. Zelin speculates that 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.[1. CNN – Doubts surface over e-mail on claim of responsibility for Benghazi attack http://security.blogs.cnn.com/2012/10/24/doubts-surface-over-e-mail-on-claim-of-responsibility-for-benghazi-attack/]