Stza was performing at a protest concert in the area, which is also home to the NYPD's 9th Precinct, and proceeded to throw donuts at officers while performing. After the set Stza was arrested. The Village Voice dug into the incident, explaining some of what happened:
[Promoter Bill Cashman] says police are applying a double standard to Leftover Crack, and effectively taking away their freedom of speech. "For them, they strictly enforce the rules," he says. "But for other performances, they don't. The Charlie Parker Jazz Festival, the Theater for a New City, the recent performance by the Undead, were all way louder. No one was there from the police enforcing it. They just want to keep our shows quiet."
You can find the rest of the article here.