This attack was coordinated, IMO by al-Qaeda. The Cairo attack was a diversion for the media and world to keep eyes on an already hotbed for radical islam while the assassination of Ambassador Stevens and 3 staff members was carried out.
The anti-muslim video has been out around for a while and is being used as an excuse.
(FYI if you aren’t aware or wondered why the formal intro The Blaze tv is now back on tv via DISH Network!)