Obama Doctrine: Admin Withdrew Special Forces Team From Libya One Month Before Attack CBS News has learned that congressional investigators have issued a subpoena to a former top security official at the US mission in Libya. The official is Lt. Col. Andy Wood, a Utah National Guard Army Green Beret who headed up a Special Forces "Site Security Team" in Libya. Lt. Col. Andy Wood led a 16-member Special Forces site security team responsible for protecting U.S. personnel in Libya. The subpoena compels Lt. Col. Wood to appear at a House Oversight Committee hearing next week that will examine security decisions leading up to the Sept. 11 Muslim extremist terror assault on the U.S. compound at Benghazi. U.S. Ambassador Christopher Stevens and three of his colleagues were killed in the attack. Lt. Col. Wood has told CBS News and congressional investigators that his 16-member team and a six-member State Department elite force called a Mobile Security Deployment team left Libya in August, just one month before the Benghazi assault. Wood says that's despite the fact that US officials in Libya wanted security increased, not decreased. Wood says he met daily with Stevens and that security was a constant challenge. There were 13 threats or attacks on western diplomats and officials in Libya in the six months leading up to the September 11 attack. A senior State Department official told CBS News that half of the 13 incidents before September 11 were fairly minor or routine in nature, and that the Benghazi attack was so lethal and overwhelming, that a diplomatic post would not be able to repel it. Wood, whose team arrived in February, says he and fellow security officials were very worried about the chaos on the ground. He says they tried to communicate the danger to State Department officials in Washington, D.C., but that the officials denied requests to enhance security.