“I think that Breivik was a turning point, because he was sort of a proof of concept as to how much an individual actor could accomplish,” said J.M. Berger, author of the book “Extremism” and a research fellow with VOX-Pol, a European academic initiative to study online extremism.
“He killed so many people at one time operating by himself, it really set a new bar for what one person can do.”
LINK: https://www.nytimes.com/interactive/2019/04/03/world/white-extremist-terrorism-christchurch.html