Experts who monitor hate groups say the attacks on Friday at the mosques in Christchurch, New Zealand, follow a sharp rise in violent white extremism around the globe and especially in the United States.
"They operate in an ideological world of people that reinforce each other's ideas but may never actually meet each other in person," says Kathy Blee of the University of Pittsburgh, who studies white extremism.
It's a common misconception that the average white supremacist is a disaffected white guy with economic anxieties. Blee's research shows that middle-class and even upper-middle-class men from the mainstream are increasingly being drawn into this movement, which is mostly online and worldwide.