I don't think this case involves much conspiracy theorizing. I was one of several on this forum at the time saying it was obvious Islamic terrorism when the White House was going on about demonstrations over a cheesy video, even while we were seeing live footage of hundreds of people with Al Qaeda flags on the grounds of the US Embassy in Cairo. Then we find out that indeed that an Al Qaeda sympathizing (or member?) group claimed responsibility early on.
I think ultimately this is a coverup to hide epic incompetence.