Outside ‘agitators’ in protests have a long history – in myth and fact

As the Los Angeles Police Department moved to box in a group of protesters outside the city’s downtown federal building last weekend, several people suddenly rushed the line.

Chunks of concrete flew through the air, recalls Martín Hoecker-Martinez. He says a woman then ran up and down the group of bystanders, exhorting others to join the attack.

“Whether she recruited people, I don’t know,” says Mr. Hoecker-Martinez, a college physics professor who had been peacefully walking the Los Angeles streets waving U.S. and Colombian flags. But she was “clearly communicating to get more people” to push back against the police.