From ABC News last February:

by Cornell Barnard Friday, February 03, 2017

BERKELEY, Calif. (KGO) — Some call it a group, others call it a tactic but regardless, Black Bloc caused a lot of damage at U.C. Berkeley Wednesday.

RELATED: Police criticized for lack of action during Berkeley protests

Many blamed violent protests on campus on a small group of demonstrators and their military-style tactics.

Swarms of people dressed in black unleashed chaos on the campus, invading what was billed as a peaceful protest against right-wing commentator Milo Yiannopoulos.

“They asked Black Bloc to stay non-violent,” said U.C. Berkeley professor Katrin Wehrheim. She says student protesters made that request of the anti-fascist group, but it didn’t happen.

The group smashed windows, tossed smoke bombs, set fires and fought with police. The event was quickly canceled.

Student Chris Vinan said, “It was very organized and thought out.”

Most recently, Black Bloc has launched protests opposing Donald Trump.