Clashes between demonstrators and police marred the end of what had been a largely peaceful second day of protest rallies in St. Louis following the acquittal of a police officer in the fatal shooting of a black man.
Several hundred people gathered near Washington University as the main rallies and marches wound down yesterday evening.
As the night wore on violence broke out between some of the roughly 100 remaining protesters, some holding bats or hammers, and riot-clad police who ordered them to disperse.
Shop and restaurant windows were smashed, including at businesses crowded with patrons and demonstrators hurled rubbish bins at officers, who numbered around 200.
Police declared the scene an unlawful assembly and threatened to deploy tear gas and arrested at least eight people.
Elisheva Heit, whose flower shop window was smashed on the eve of its grand opening, said "I don't understand how this would bring the poor guy back to life."
Sweeping up glass, she asked passing officers "This is how you protect people?"
The demonstrations began peacefully on Friday after Circuit Judge Timothy Wilson acquitted former St. Louis Police Officer Jason Stockley of first-degree murder in the shooting death of 24-year-old Anthony Lamar Smith.
The verdict came about three years after rioting broke out in the St. Louis suburb of Ferguson when a black teenager was shot dead by a white police officer.
After Friday's ruling, some 600 chanting protesters marched from the courthouse through downtown St. Louis.
Later, some broke windows at a library and two restaurants and threw bricks and bottles at officers, who used tear gas and rubber bullets to disperse the throng.
At one point, demonstrators threw rocks and paint at the home of St. Louis Mayor Lyda Krewson, police said.
Smith was shot five times in his car after attempting to elude Stockley and his partner, who had chased the suspect after an alleged drug deal, authorities said.
During the pursuit, Stockley could be heard saying on an internal police car video he was going to kill Smith, prosecutors said.
Stockley believed that Smith was armed, defense attorneys said, and a gun was found in the car. Prosecutors argued Stockley planted the weapon and the gun had only Stockley's DNA.