The shooter appears to have been very familiar with extremist corners of the internet.
The guns used in the attack were also decorated with memes, mostly insider white nationalist references. Then, right before the starting the attack - which he live-streamed to Facebook as if it were a first-person shooter video game - the shooter referenced the “subscribe to PewDiePie” meme. In the post, he wrote that it was “time to stop shitposting and time to make a real life effort” - meaning, essentially, that it was time to stop fooling around on the internet and turn his extremist views into real-world action.
The shooter posted the manifesto, along with a link to the forthcoming live stream of the promised attack, on 8chan, one of the main online homes of meme-loving right-wing extremists. The document rails against Muslims and immigrants and includes several references to memes and video games. Police are currently investigating a sprawling 74-page manifesto that the 28-year-old suspect allegedly wrote and posted on social media shortly before the attack. The man who allegedly shot and killed 49 people at two mosques in Christchurch, New Zealand, framed the attack as a real-life escalation of meme-based internet culture.