From CNN’s Donie O’Sullivan

On Saturday afternoon, an anonymous user on the online forum 4chan wrote, “just 20 mins ago I just witnessed a mass shooting at a tops supermarket live on twitch with like 20 other viewers.” 

The hate-filled forum 4chan, where all users post anonymously, appears to be at the center of the made-for-the-internet massacre that took place in a Buffalo supermarket on Saturday — from discussion on the platform apparently helping inspire the alleged attacker to spreading the gruesome video of the shooting.  

A 180-page document that has been attributed to the man suspected of the shooting, in which 10 people were killed, references how he was influenced by what he saw on 4chan, including how he was inspired by watching a video of the 2019 mass shootings in Christchurch, New Zealand — which were also streamed live.  

Ben Decker, the CEO of Memetica, a threat analysis company, told CNN, “this is a step-by-step copycat attack of Christchurch, in both the real-world attack; planning and selecting the target, and online; coordinating the livestream and manifesto dissemination across fringe message boards.” 

4chan, which was created in 2003, claims it receives 22 million unique visitors a month, half of whom it says are in the United States.