https://www.cnbc.com/2019/03/21/why-facebooks-ai-didnt-detect-the-new-zealand-mosque-shooting-video.html

Facebook explained why its artificial intelligence tools failed to detect the video of the New Zealand mosque shooting live streamed on its site last week before being viewed 4,000 times. A suspected gunman killed 50 people in an attack on two mosques in the area.

The video was removed by Facebook after being flagged for the first time by a user 29 minutes after the stream began, the company said in a blog post Wednesday night. Several social media platforms removed the original video from their sites, but quickly saw copies pop up at a clip with which their moderation systems couldn't keep up. Users also altered the video to slow down automatic detection.