BBC News :

The man accused of the Christchurch shootings left a trail of references to online culture and extremist alt-right ideology.

When he first appeared in court, Brenton Tarrant flashed an “OK” hand sign.

The gesture was described in some accounts as a white nationalist symbol, but perhaps more accurately could be called a trollish gesture. It is used by extremists, but also by a range of conservatives, far-right figures and the alt-right – a disparate group of activists who congregate on extreme message boards.

A document posted shortly before the shooting and widely credited to the suspect, indicates the author is steeped in the alt-right’s toxic culture.

Online, white nationalist ideology hides under layers of irony, often allowing its proponents to duck accusations of extremism while actively spreading hateful language and memes.

Cultural references

Potential clues to the New Zealand’s suspect’s ideology and inspiration also appear in a live-streamed video which social networks have struggled to completely take down.

The written document was posted on the extreme message board 8chan shortly before the attack began on Friday. It has been called it a “manifesto” but that term rather grandly overstates a confused jumble of thoughts and misinformation which rambles on for 74 poorly-written pages.