Seriously. This is the latest fever dream from the right. They believe that the reason Ambassador Chris Stevens was in Benghazi on September 11 was to negotiate the return of Stinger missiles that Hillary Clinton had sold to Al Qaeda groups over the objections of the CIA.
Why couldn't the wingers be happy with their old complaint: that Obama had done too little after the Libya war to secure Muammar Qadafi's arsenal of shoulder-mounted antiaircraft missiles,1 thus allowing them to fall into the hands of assorted bad guys in the Middle East? That's at least based on a kernel of truth. Beats me. Because it didn't involve Hillary Clinton, I guess, and therefore wasn't a perfect conspiracy theory.
1For the record, old Russian SA-7s, not Stingers. More here.