FERGUSON, Missouri — The second day of protests over a grand jury's decision not to indict a police officer in the shooting death of Michael Brown turned violent late Tuesday.
Protesters set a police car on fire and smashed windows at businesses that hadn't already boarded up their storefronts. Dozens of people were arrested on what authorities characterized as a "much better night."
For most of the day, there had been only occasional arrests and streets had largely remained clear, police told NBC News. National Guard members were posted near police headquarters but left matters to local officers for the most part.
Around 9:55 p.m. local time (10:55 p.m. ET), a small group of protesters began breaking the windows of a police cruiser. The group tried but failed to overturn the car, but someone tossed an incendiary device at it, and the vehicle caught fire.
About a dozen police cars responded, arriving at the scene from two directions. An announcement went out over a loudspeaker: "This has turned into an unlawful protest. You must disperse or you will be arrested, even media."
The National Guard troops began getting involved about 11 p.m. as 150 or so protesters gathered at Ferguson police headquarters, spilling into the streets. Guard troops stepped out from behind their barricades, joining local police in a rectangular formation with their protective shields raised, trying to move the protesters back from the building and two armored law enforcement vehicles that were at the scene. It couldn't immediately be determined whether the armored vehicles were Guard or police units.
Authorities began spraying protesters with an irritant. In the parking lot across from the police station, a man slumped to his knees crying and clutching his eyes as others tried to use milk and napkins to wash his eyes out.
An NBC News reporter witnessed five people being arrested and taken into police headquarters during the late-night confrontation.
Punctuated by the sound of shattering glass, groups of protesters threw rocks at St. Louis County police vehicles and several storefronts after midnight. Someone threw a small firework into a car care center, which was immediately set upon by people breaking windows as a thin column of smoke rose from the building. County police soon arrived in reinforced vehicles bearing long guns, believed to be armed with rubber bullets. By about 1 a.m., streets were clearing and appeared to be settling down.
"This is the police with weapons, and it's not fair," said Symonne Sparks, a 22-year-old college student. "It's saddening and hurts my heart. All I've been doing is trying to have a peaceful protest. ... I'm more afraid of the police than the protesters, even though we've seen the looting. People are more scared of the police."
The state Department of Public Safety confirmed some damage at Ferguson City Hall on Tuesday night, tweeting a photo of a shattered glass door.
Onni Love, who lives in an apartment building near the street where the car was torched, said the confrontations were upsetting, "but I can't blame them because of the unjust things that have happened in the community."
Love, 36, said she was outside Tuesday night trying to protect her building.
"I'm doing this for my kids' safety and my safety. I have a grandbaby," Love said. "I want people to know this isn't all businesses. This is a residence. I live here."
M. Alex Johnson and Dan Shepherd of NBC News contributed to this report.