When police in Washington DC burst into a fifth-floor apartment building on 22 April in search of a man who allegedly had shot four people at random, they found Raymond Spencer dead by his own hand, a cache of guns and ammunition, and a poster with an ironic white supremacist meme.

The poster invoking the meme, popular on the extremist online forum 4chan, was a stark reminder that this attack blamed on Spencer, 23, was only the most recent mass casualty attack to spawn out of the ugly extremist culture of unregulated internet message boards such as 4chan…

Just two minutes after the shooting began, someone under the username “Raymond Spencer” logged onto the normally-anonymous 4chan and started a new thread titled “shool [sic] shooting”. The newly published message contained a link – to a 30-second video of images captured from the digital scope of Spencer’s rifle. The clip streamed images and sounds of the barrage of bullets which slammed into cars and shattered windows at an adjacent school while also maiming four strangers.