As the search continues for those directly involved in last week’s killing of U.S. Ambassador to Libya, Chris Stevens, and the attack on the embassy in Benghazi, it has been revelaed that a former inmate of the Gunatanamo Bay detention facility may have been the leader of the attack.

Former inmate Sufyan Ben Qumu, one of the leaders of Ansar al-Sharia, a militant Islamist group based in Derna, Libya, has been identified by local officials as being involved in the attack in Benghazi that killed the ambassador.

This information came to the UK’s Daily Telegraph via Mohammed al-Gharabi, the leader of the pro-government Rafallah al-Sehati battalion which operates in Benghazi. Although heavily Islamist, al-Gharabi and his battalion are hostile towards Ben Qumu and his militia. This makes many of those involved in the search for the perpetrators question al-Gharabi’s credibility.

“It was people from Ansar al-Sharia — not all of them but some of them, and I think (the organization) knows who did it,” said al-Gharabi.

Leaders of the Benghazi branch of Ansar al-Sharia denied responsibility but cannot speak for Ben Qumu’s group.

Fox News also claimed to have knowledge that Ben Qumu was likely to have been “involved in the attack, and even may have led the attack on the consulate.”

US intelligence confirmed the plausibility of this theory — they believe there were “communications” between Al-Qaeda and Ansar al-Sharia on the day of the attack on the U.S. consulate.

According to his Guantamo files, Ben Qumu was detained because of his involvement in the financing of the September 11 terrorist attacks. Ben Qumu was released from Guantanamo in 2007 by President George W. Bush, and returned to Libya shortly after, forming his own militia in the aftermath of last year’s revolution.