Brooklynites on Twitter reported that police followed the march and searched apartment buildings in the neighborhood without warrants, looking for children who had been seen throwing bottles at police from neighborhood rooftops.
March participants chanted "NYPD KKK how many kids will you kill today," people report from the scene.
"I'm in the middle of the riot action at Church and Snyder in my district. Right now, things are tense," New York City Councilman Jumaane D. Williams, who represents the area, said on Twitter.
Sixteen-year-old Kimani Gray was shot and killed on Saturday night after, police say, pointing a gun at approaching cops.
According to the officers involved in the shooting, the teenager adjusted his belt "suspiciously," and after they exited their vehicle to investigate, he pointed a .357 caliber revolver at them. Both officers fired at the suspect, hitting Gray eleven times in his torso and legs.
Witnesses say Gray, who was running for his life when he was shot, did not have a gun. "Stay down, or we'll shoot you again," police said once Gray had been hit, according to The New York Times.
After the shooting Gray was rushed to a hospital but was declared dead on arrival.