From NPR:

As break-ins and fires raged in the first days of mass protests over the killing of yet another black man in an encounter with police, the city seemed to descend into a security vacuum. She says the police disappeared from this neighborhood. That’s when she and others started forming patrols to include people with licensed weapons.
“I’m the one that’s checking everyone,” she says. “If you’re up here with a gun and you’re not supposed to be here and you don’t have a license to carry, then I don’t allow you to even go to the rooftop. Only people with guns are on the rooftop.”