A collaboration between ProPublica and HuffPost.
In his 74-page manifesto, Brenton Tarrant, the alleged gunman responsible for the massacres at two mosques in Christchurch, New Zealand, lays out a hyper-extreme worldview animated by racist and fascist thought.
While the authorities say Tarrant posted his treatise on 8chan — a relatively obscure web forum that attracts trolls, hackers and hardcore white supremacists — the ideas in the document are also circulating on many of the world’s most popular social media platforms.
Over the past four months, for instance, a YouTube user known as Third Positionist posted over 100 videos espousing extremist ideas that closely resemble what the authorities have identified as Tarrant’s writings. The user’s videos — full of