At least seven people have been arrested during protests in the US city of St Louis, Missouri, police have said.
The protesters were reacting to the acquittal of a white police officer charged in the fatal shooting of a black man.
Sunday night marked the third night of demonstrations and police said windows had been broken and property damaged.
Around 1,000 people had gathered in front of the police department building during the afternoon and had been protesting silently.
Later they marched along the streets, chanting "stop killing us".
But trouble began at night after organisers announced the protest had ended.
A few dozen people continued their march, damaging pot plants and breaking windows.
Kayla Reed, one of the organisers of the demonstration, said the actions of a few people had been used to "demonise" the peaceful protesters.
On Friday, a few thousands protesters had initially been peaceful but later they moved to the home of mayor Lyda Krewson, throwing rocks through a window and splashing paint on the home.
Police responded with tear gas.
Saturday saw similar scenes, with a few thousand people involved in the march, which officially ended around 9pm but up to 150 people continuing, with some eventually confronting police.
During the weekend, singers U2 and Ed Sheeran cancelled concerts in St Louis citing security concerns due to the protests.
The demonstration follows the not-guilty verdict returned on Friday for Jason Stockley, who was accused of first degree murder in the killing of Anthony Lamar Smith in 2011.
Stockley, 36, and his partner had seen what appeared to be a drug deal but, as they tried to arrest Mr Smith, he had sped away in his car.
Stockley shot at the car and said he and his partner were almost run over before they began a pursuit in their vehicle.
After two minutes, Mr Smith's car slowed down and, on orders from Stockley, fellow officer Brian Bianchi slammed the police vehicle into it.
Stockley got out of the police vehicle and shot five times into Mr Smith's car, killing him.
In court, the defence said Stockley had fired only after Mr Smith ignored commands to put his hand out and reached along the seat towards where a gun was found but prosecutors said Stockley had planted the gun.