Photo Gallery: The Danger of the Online-Bred Far Right 03/28/2019
 Brenton Tarrant, the Christchurch shooter, is responsible for murdering 50...
Mark Mitchell/ REUTERS

Brenton Tarrant, the Christchurch shooter, is responsible for murdering 50 worshippers at mosques in the New Zealand city. He livestreamed his rampage online, and when he appeared before the magistrate he flashed an "OK" signal with his hand, an ambiguous code for "white power."