From your article shows a video was the culprit that was originally said at the beginning.
On 2 July 2012, a "Sam Bacile",[11] who was later identified as Nakoula, posted English-language promotional trailers for Innocence of Muslims on YouTube. The videos were later dubbed into Arabic and posted on the internet in September 2012. Demonstrations and violent protests against the video broke out on September 11 in Egypt and spread to other Arab and Muslim nations and some western countries. The protests led to hundreds of injuries and more than 50 deaths.[