The protest of the fatal police shooting of a man selling CDs in Louisiana’s capital of Baton Rouge had many of the trappings of similar flare-ups around the country: blaring music, young men with faces obscured by bandannas, and obscene and brutal sentiments directed toward the local police department, on angry tongues and homemade placards.

But as Wednesday night’s street rally flowed into Thursday morning, it had managed to be as peaceful as it was passionate, the New York Times reports. Cars and trucks honked, stopped and skidded as they made their way up and down a few blocks of North Foster Drive, past cheering and dancing crowds in front of the Triple S Food Mart where Alton Sterling, 37, was fatally shot early Tuesday by officers responding to a call about an armed man.

The Justice Department opened a civil rights investigation into Sterling’s death after a video of the encounter, shown repeatedly on television and social media, reignited contentious issues surrounding officer-involved shootings.

Officials from Gov. John Bel Edwards to the local police and elected officials vowed a complete and transparent investigation and appealed to the city — after a numbing series of high-profile, racially charged incidents elsewhere — to remain calm.