Demonstrators had gathered in the city centre for a protest that started peacefully but turned disorderly after dark, following the pattern seen on Friday and Saturday.
Protesters smashed windows and attempted to block a ramp to an interstate highway, police and witnesses said.
Most police and protesters left the area after about two hours, though police continued ordering people to disperse.
Officers tackled some protesters who defied police orders, and more than 80 people were arrested.
At a late-night news conference, Mayor Lyda Krewson noted that "the vast majority of protesters are non-violent," and blamed the trouble on "a group of agitators."
Demonstrators protest outside the St. Louis Police Department headquarters in response to a not guilty verdict in the trial of former St. Louis police officer. Source: AAP
The protests in St Louis follow the acquittal on Friday of former police officer Jason Stockley, 36, of first-degree murder in the 2011 shooting death of Anthony Lamar Smith, 24.
The violence evoked memories of the riots following the 2014 shooting of a black teenager by a white officer in nearby Ferguson, Missouri.
Serious clashes broke out in 2014 in Ferguson, a suburb of St. Louis, following the killing of 18-year-old Michael Brown by a white police officer who was not indicted.
The Ferguson protests gave rise to Black Lives Matter, a movement that has staged protests across the United States.
2011 shooting
Stockley shot to death Anthony Lamar Smith, a black man, in 2011 after a car chase that followed an attempt to arrest Smith for a suspected drug deal.
Stockley maintained he shot Smith in self-defense, but he was caught on an in-car camera video telling his partner, Brian Bianchi, "Going to kill this (expletive), don't you know it."
Prosecutors brought first degree murder charges in 2016, alleging that Stockley's comments showed premeditation and that he had planted a silver revolver in Smith's car.
But Judge Timothy Wilson acquitted Stockley, finding that the evidence on the gun, as well as the officer's videotaped comment, provided insufficient grounds to convict.
Marching through two shopping malls on Saturday, protesters chanted, "The whole damn system is guilty as hell."
"We will not tolerate violence," Acting Police Chief Lawrence O'Toole told reporters.
Cancellations
The U2 and Ed Sheeran concerts were among several events cancelled over the tense weekend.
Others included a St. Louis Symphony Orchestra concert and a "Shakespeare in the Streets" event.
Entertainment firm Live Nation and U2 jointly announced the cancellation of that group's scheduled Saturday show in a statement citing concerns about fans' security.
People run after vandalizing as demonstrators march in response to a not guilty verdict in the trial of former St. Louis police officer Jason Stockley in 2017. Source: AAP
"We have been informed by the St. Louis Police Department that they are not in a position to provide the standard protection for our audience as would be expected," they said.
"We cannot in good conscience risk our fans' safety."
U2 superstar Bono later posted on Instagram that he was "deeply saddened at what has happened in St. Louis" and had asked himself, "Is this 1968 or 2017?"
And Briton Sheeran, in announcing that he was pulling the plug on a show set for Sunday, said he hoped to return as soon as possible.
Left: Anthony Lamar Smith was shot to death by Jason Stockley in 2011. Source: AAP
'I'm not the guy'
In an interview with the St. Louis Post-Dispatch, Stockley said he understood how the video might look bad to investigators and the public.
"I understand what the family is going through, and I know everyone wants someone to blame," he said, "but I'm just not the guy."
