After months of tension, marches and sporadic violence, and then the unbearable anxiety of waiting over the past few days, there was a surreal pause just past 8 p.m. local time Monday on the streets of Michael Brown’s home town.

At the center of the crowd blocking the avenue in front of police headquarters, in a car with a masked man at the wheel, someone turned up the radio so the demonstrators could hear the prosecutor’s news conference.

The hundreds of protesters became as solemn and quiet as the officers posted in a long line behind a barricade. The prosecutor’s voice droned. The crowd leaned in to hear.

And then — pandemonium.

“It’s legal to kill unarmed black men in America!” shouted a man known as T. Dubb standing on top of the car with a gas mask slung over his baseball cap. Shortly, he would need the mask.

A portion of the crowd peeled off and sprinted toward the barricade. Several water bottles were hurled at the officers, who batted them away with plastic shields. The protesters began chanting obscenities.

With that pause for the prosecutor, they had forgotten the one requested by the Brown family — 4 1/2 minutes of silence before the demonstrations began, to mark the 4 1/2 hours his body lay on Canfield Drive.

Soon South Florissant Avenue was a chaotic scene of shifting lines of police and protesters, moments of calm and minutes of brief panic and anger as some demonstrators taunted police and others fled, only to surge back again. The majority of protesters were peacefully passionate. Police fired tear gas. Two police cars were engulfed in flames. Glass from half a dozen smashed shop windows — among them a beauty shop, a hardware store, a Chinese restaurant, a dentist’s office — glittered in the gleam of police spotlights and television cameras.

There was little looting here, except for the bewigged mannequins that young men dragged from the beauty shop into the street.

“I feel like the verdict was unfair, that it shouldn’t have taken so long to reach it,” said Duane Coats, a calm voice amid the cries and profane jeers, an elder with the Christian Faith Center. His task, he said, was to stop protesters from throwing bottles and persuade them to stick to peaceful actions. Protest organizers had deployed him and other clergy members to the likely hot spots in greater St. Louis to try to urge nonviolence.

“I need to be here with my people,” said Carlos Ball, a demonstrator who was holding a poster with a picture of his brother, Cary, who he said was killed by police in St. Louis in 2013. “It’s the same struggle. I’ve got two sons, nieces and nephews. If it takes my fighting for them so they can live and be peaceful, that’s what I got to do.

Officers moved up and down the street, attempting to clear parts of the crowd and making several arrests.

A grand jury has declined to indict Ferguson, Mo. police officer Darren Wilson in the shooting death of 18-year-old Michael Brown. Here is a look back at the events following the August shooting. (Gillian Brockell and Sarah Parnass/The Washington Post)

“How am I under arrest for arson? I don’t even have a lighter. I didn’t do anything. Tell me who saw me?” screamed Robert Kalbfell as officers led him to the back of a lock-up van. He said he was a part-time university student who lives in Ferguson.

“I didn’t do anything!” He yelled. “Someone help me.”

Around 10:30 p.m., officers attempted to clear even more of the crowd — pushing people up the road toward Marley’s, a local watering hole where regulars sat behind locked doors watching the action both on television screens and through glass windows.

As they tried to force the demonstrators to move, some officers had heated exchanges with members of the clergy who attempted to serve as intermediaries. Officers pushed them aside and demanded that the crowd move from the sidewalk.

“Ron Johnson is getting a call from me tomorrow,” declared Pastor Robert White, who leads a congregation in downtown St. Louis and was wearing a bright orange “Clergy United” T-shirt. He was referring to the Missouri Highway Patrol captain. “This proves that all of that training was just training in how to arrest people, not how to de-escalate.”

At nearby Wellspring United Methodist Church, volunteer medics brought two women suffering from the effects of tear gas to recuperate.

Earlier, just before the announcement of the grand jury decision, the crowds were much sparser at locations that have become totemic stopping points for supporters and mourners. Rodney Jones took a 360-degree panoramic video of the corner of West Florissant and Ferguson avenues. He grew up here, moved a short distance away and came back to make sure his parents were safe.

“I came to see what the reaction is,” Jones said. “This is uncharted waters for everybody.”

Within hours, a nearby building would be in flames. But for now, through his viewfinder, Jones could see knots of young men beginning to cluster in the parking lot of the McDonald’s and in shopping strips where most of the businesses have plywood over their windows — a defense against possible looters — even though they remain open. The McDonald’s was locked early on this night. So was the liquor store where Brown made his last stop before walking down Florissant, turning right on Canfield and encountering Officer Darren Wilson.

On toward Canfield, the boarded-up chop suey restaurant was doing a brisk business and planned to stay open at least until the decision was announced. “After that, I don’t know,” said the guy slinging chicken fried rice and egg-drop soup.

A small group of residents gathered on Canfield, beside the memorial of stuffed animals and flowers near the spot where Brown fell. A man who would give only his middle name, Akeem, because he said he was too outspoken for his own safety, marched around the memorial hundreds of times in the hour before the decision was announced.

“They gotta stop killing black people for nothing,” he said. At 30, he has a 1-year-old son. “Fifteen years from now, he could be walking down the street and he gets executed.”

Preparations for action

Protest groups said they had scouted locations throughout the area for demonstrations and civil disobedience. Clergy members fanned out to try to counsel calm amid gathering crowds. Legal observers were on hand to take notes on any confrontations with police. And an activist collective of young residents called Copwatch carried video cameras to document police actions.

The hope had been to avoid a repeat of the first furious wave of demonstrations in the weeks after Brown’s killing — which included looting, the burning of one business and occasional gunfire. Then, heavily armed police fired tear gas and rubber projectiles at demonstrators.

This time, police and protesters had 3 1/2 months to plan and prepare. Organizers and police had hoped that their recent negotiations over rules of engagement would lead to more peaceful action in the streets after the grand jury decision.

Local protest groups conducted thousands of hours of training for hundreds of supporters in peaceful direct action and understanding their legal rights. They distributed information about support if they are jailed and available lawyers.

County and state police, meanwhile, trained in how to handle civil disobedience and de-escalate encounters with demonstrators.

By midnight Monday, however, the best-laid plans still resulted in flames, window smashing, tear gas and more than two dozen arrests.