At least 49 people died in shootings at two mosques in Christchurch, New Zealand. Authorities identified the heavily-armed shooter as a 28-year-old Australian. He live-streamed his attack on Facebook. The video quickly spread across social media platforms. Moderators at sites like Twitter, Reddit, and Facebook say they’re working to contain the horrific video. Social media has provided a platform for right-wing hate groups to spread their ideology. They’re now being criticized for their slow response to the spread of this video.