A former Occupy Wall Street organizer, Mr. Bray said he isn't part of the antifa movement, but he was able to conduct extensive interviews with anonymous antifa activists by agreeing to speak to them by phone or on encrypted message boards.
Antifa rise after Charlottesville alarms free-speech advocates
"In the abstract. I'm going to leave it at that if you don't mind," said Mr. Bray.
Mark Bray, Dartmouth professor, calls 'vital' Antifa violence 'collective self-defense'