Violence broke out near the Ferguson Police Department on Monday night after the announcement that the officer who killed Michael Brown last summer would not face charges.
Two police cars were set ablaze and burned out of control. The ammunition inside could be heard going off in volleys as the flames consumed it.
Earlier, when several hundred demonstrators outside police headquarters heard that the grand jury had declined to indict Officer Darren Wilson, a protester began to run through the crowd shouting, "Our lives don't matter! Our lives don't matter! Our lives don't matter!"
Soon, about two-thirds of the crowd moved a couple of blocks down the street and confronted police. Officers responded with tear gas and smoke grenades. An officer with a megaphone told the protesters to back up, warning that they would be arrested if they didn't get off the street.
Gunshots rang out, but it was unclear where they came from.
Police in riot gear chased protesters.
As the police cars were consumed, about 100 people stood on the sidewalk and watched them burn.
Kisha Cole ran down the middle of the street, screaming that a woman had had a heart attack and needed help. She said she ran up to the police to ask them to help the stricken woman, but officers fired tear gas instead.
"We were standing right next to her," she said. "We tried to get them to help her and they fired tear gas at her."
Back at the police headquarters, about 60 officers in riot gear took cover behind police cars as protesters threw bottles, rocks and at least one megaphone. Officers were on their knees, holding their shields above their heads to protect themselves from projectiles.
"Don't throw it!" an officer shouted at the crowd.
Before violence erupted, dozens of officers stood behind metal barricades as scores of people shouted insults.
When riot police hurried to take up a position farther from the crowd, someone yelled, "Run, you cowards!"
An officer on the police line dropped his baton, then quickly picked it up.
"What's up, bad boy?" said a protester in a black mask who identified himself as Marcus Skull.
The riot-gear clad officer nodded in acknowledgement.
"You ready for this tonight?" Skull yelled again.
Again, the officer nodded.
"Then you'd better keep your hand on your baton," Skull said.
Sara Randall, 21, stood nearby with her hands in her coat pockets as she shivered in temperatures that dropped into the mid-30s.
"I expected this. No indictment," said Randall, who came from Denver. "Did I have hopes that justice might be served in this case? Yes I did."
College student Olunife Hassan, 22, shook his head and said he hadn't expected an indictment. What bothered him was the reaction of much of America, he said, that the killing in Ferguson wasn't an important turn of events.
"I could go on Facebook right now and hear people saying, 'What's the big deal? What's so different in Ferguson? This happens all the time,' he said.
"It's not that it happened before," he said, "but that it happened again."
Tommy Brown, 12, stood at the police barricade. "The government's just messed up," he said.
His mother, Marian Brown, said she brought all three of her children – Tommy, Gaubrielle, 18, and Mariah, 13 – to the demonstration, despite the risk of violence.
If the mood of the crowd turned, she said, she would take them home. But the children's great-grandparents had marched with Martin Luther King, she said, so she wanted her children to see "this is the possibility of what can happen when you deal with the police in Missouri."
Tommy interjected: "They're racists."
Marian Brown said her ex-husband, a police officer in a nearby city, had warned the family that Wilson would not be indicted. But they held out hope.