FERGUSON, United States (AP) — Ferguson business owners and residents spent yesterday boarding up windows and clearing debris after two nights of unrest over the grand jury decision in the Michael Brown case, even as protesters continued to hold scattered demonstrations in the area.

Several protesters managed to rush into St Louis City Hall screaming “Shame, shame,” leading police to lock down the building and call in more than a hundred extra officers. Police arrested three people, including one on an assault charge.

The demonstrators were among a group of about 200 that marched through downtown St Louis and held a mock trial of Darren Wilson, the Ferguson police officer who shot and killed the unarmed Brown during an August 9 struggle in that St Louis suburb.

In Ferguson, meanwhile, many residents eager to get back a sense of normalcy were hoping to replace the night-time chaos and unrest since Monday’s announcement of the grand jury decision with the relative calm the city has enjoyed during daylight hours. About a dozen people were painting over boarded-up windows on businesses in the suburb’s downtown yessterday, where National Guardsmen were stationed every few feet and some looked down from rooftops.

“This is my Ferguson, you know?” said Kari Hobbs, 28, as she watched 17-year-old Molly Rogers paint “Love Will Win” on a board that covered a smashed window at Cathy’s Kitchen, a restaurant not far from the Ferguson Police Department.

There were no seats inside Cathy’s Kitchen yesterday, and a line had formed at the back of the building. As light snow fell, a diverse mix of residents, businesspeople with the day off and journalists covering the protests enjoyed a pre-Thanksgiving lunch.

Jerome Jenkins, who runs the restaurant with his wife, Cathy, said he never considered closing his doors.

“Me and my wife, we expected it to get damaged … we decided to go home, and we would live with whatever fate would give us.”

He said it was protesters who helped spare his business during Monday night’s chaos, when a dozen commercial buildings were burned to the ground.

“The criminals, the looters, whatever you want to call them: They’re not protesters, they wanted to vandalise the place,” Jenkins said. “And the protesters locked arms together and they surrounded our place and … told them ‘No, you’re not going to touch this place.'”

An influx of guardsmen helped make Tuesday night much calmer, although there were still 58 arrests at area protests and demonstrators in Ferguson set fire to a squad car and broke windows at City Hall.

There have been demonstrations in cities throughout the US since the grand jury’s decision was announced. Most have been peaceful, with protesters rallying behind the refrain “hands up, don’t shoot”. But others haven’t been calm, including a demonstration in Oakland, California, in which protesters vandalised several businesses, one in Minneapolis in which a car struck a protester and drove into others. And in Portland, Oregon, police used pepper spray and made arrests after about 300 people disrupted bus and light rail traffic.

Wilson, 28, broke his long public silence on Tuesday, saying during an interview with ABC News that he has a clean conscience because “I know I did my job right.” Wilson, who had been on the Ferguson police force for less than three years before the shooting, said Brown’s shooting was the first time he had fired his gun on the job.

Asked whether the encounter would have unfolded the same way if Brown had been white, Wilson said yes.

The Justice Department has also launched a broad probe into the Ferguson Police Department, looking for patterns of discrimination.

Attorney General Eric Holder said the department aims to complete those investigations as quickly as possible “to restore trust, to rebuild understanding and to foster cooperation between law enforcement and community members”.