Protest organizers said that no matter what Mr. Brown had been doing with his hands when he was shot — balling them, holding them out or pulling up his pants, according to various witness accounts outlined by the Justice Department — he had still been shot at least six times, and his body had been allowed to lie in the street for hours.

They said that “hands up, don’t shoot” had taken on a power of its own that arced beyond Ferguson, becoming a broader evocation of anger and injustice that now stood with earlier protest calls like “si, se puede,” “we shall overcome” or “I can’t breathe,” one of the last things said by Eric Garner, a black man who was killed in a chokehold by a white New York police officer on Staten Island.

“ ‘Hands up, don’t shoot’ has become a larger symbol of the desire to prove one’s innocence,” said Donna Brazile, a Democratic strategist who is African-American and has spoken out forcefully about police practices in Ferguson, in an email message. “In many ways, it will always resonate as a symbol of an unarmed dead teenager lying for hours on the street. Just like ‘I can’t breathe’ will never go away. They are forever etched in the complicated story of racial bias in our criminal justice system.”