WASHINGTON — President Joe Biden urged calm in the Minneapolis suburb of Brooklyn Center after a night of palpable anger in the streets over the police killing of a 20-year-old black man in a traffic stop. The president said he had seen the body camera footage of the shooting. “We do know that the anger, pain and trauma amidst the black community is real,” Biden said from the Oval Office. Even so, he said there was no justification of violence and looting.