Interesting enough, David Ubben father was quoted back in a Sept. 20, 2012 article from the NYT’s, so David’s story was available quite a while ago to journalist.
From the article “American counterterrorism officials and Libyans on the scene say the mortar attack was most likely carried out by the same group of assailants who had attacked the mission and then followed the convoy of American survivors retreating to what they thought was a safe house.
The first mortar shell fell short, but the next two hit their mark in rapid succession with deadly precision, according to an account that David Ubben, one of Mr. Stevenss security guards, told his father, Rex Ubben, which was supported by other American and Libyan officials.
There are three villas inside and the walls are high, and the only house that got hit was the house we were in, said Fathi el-Obeidi, a Libyan militia commander who came to help evacuate the Americans.
This indicated that many of the assailants were practiced at aiming their mortars, skills they learned in fighting Col. Muammar el-Qaddafis army.
David did not draw a distinction between the attackers, Rex Ubben said in a telephone interview. David Ubben, a 31-year old Iraq war veteran, was wounded in the mortar attack, and is recovering from his wounds at Walter Reed National Military Medical Center in Bethesda, Md. His father said he had declined to speak to reporters”
article here - > http://www.nytimes.com/2012/10/01/world/africa/mistaken-sense-of-security-cited-before-envoy-to-libya-died.html?pagewanted=all&_r=0