Coalition members said tension was growing, fueled by other fatal police shootings and long-term problems of racial profiling, a lack of diversity and accountability in law enforcement, inequality and a lack of trust in police and the judicial system. They also cited failure of authorities to arrest Wilson and leaks to news media about the investigation.

The group blamed police for escalating peaceful protests into violence, saying that given proper space, protesters had been self-policing.

Montague Simmons, chairman of the Organization of Black Struggle, said he expected Clayton and the Ferguson police station to be “natural gathering areas” after the decision was announced.

People “are going to pour into the street,” he predicted, adding that no amount of force would prevent that. But he said that the coalition would engage in “peaceful, nonviolent civil disobedience” in the tradition of Mahatma Gandhi and the Rev. Dr. Martin Luther King Jr.

“Every injury, every bullet that flies, every drop of tear gas,” he said, will be on the hands of elected officials if they fail to act.