Demonstrators burn a flag in St. Louis to protest a court finding a former police officer not guilty of murdering a man. (Screen capture)

(CNSNews.com) - Protesters in St. Louis, Mo., on Friday night injured nine police officers and burned American flags to express their disagreement with a court determining that a former St. Louis police officer was not guitly of murdering man.

"Many of the demonstrators were peaceful," Acting St. Louis Police Chief Lawrence O'Toole told reporters. "However, after dark, many agitators began to destory property and assault police officers."

"Orders to disperse were given numerous times," O'Toole said. "Tear gas was deployed after officers were assaulted with bricks and bottles. Officers did deploy pepper balls as a less-than-lethal weapon after agitators continued to assault officers with objects and destroy property."

According to the St. Louis Post-Dispatch, about 1,000 protesters gathered outside the home of Mayor Lyda Krewson, breaking some of her windows and throwing red paint on her house.

Video of the protests shows demonstrators burning American flags.

Other properties, according to the paper, including local restaurants were damaged by the demonstrators.

The protests were sparked by the not guilty verdict brought against former Police Officer Jason Stockley.

"Stockley, who is white, was charged with muder in the 2011 shooting death of black drug suspect Anthony Lamar Smith," reported the Post-Dispatch. "his acquittal in a bench trial early Friday sparked the protests downtown and in the Central West End."