https://phys.org/news/2019-03-facebook-15mn-christchurch-videos-criticism.html

Facebook said it "quickly" removed the video, plus the gunman's account and Instagram, and in the first 24 hours scrubbed 1.5 million videos worldwide "of which 1.2 million were blocked at upload."

Spokeswoman Mia Garlick from Facebook New Zealand said the firm was "working around the clock to remove violating content using a combination of technology and people."