https://www.cnet.com/news/new-zealand-mass-shooting-shows-tech-companies-cant-control-viral-tragedies/

The violent video was downloaded from Facebook. Then it was re-uploaded to YouTube multiple times, often within minutes of each other. YouTube is encouraging users to to flag any videos showing this clip and said it has been removing thousands of videos related to the shooting in the last 24 hours.

"Shocking, violent and graphic content has no place on our platforms, and we are employing our technology and human resources to quickly review and remove any and all such violative content on YouTube," a YouTube spokesperson said in a statement. "As with any major tragedy, we will work cooperatively with the authorities."