Sept. 22 (UPI) -- The American Civil Liberties Union on Friday filed a lawsuit against the city of St. Louis for what it described as the unconstitutional treatment of people protesting the acquittal of a white police officer who fatally shot a black motorist.
The ACLU of Missouri accused the St. Louis Metropolitan Police Department of misconduct using chemical weapons, interfering with video of police activity and violating due process.
The organization in particular took issue with officers' use of the controversial crowd control technique known as "kettling," in which police close in on protesters from all sides, preventing them from leaving an area before arresting them.
Protesters said the St. Louis police used this technique Sunday night, the third night of protests of the acquittal of former officer Jason Stockley, who fatally shot Andrew Lamar Smith in December 2011.
The St. Louis Post-Dispatch reported police boxed in and arrested about 100 people in a downtown intersection, including some residents walking home and not involved in the protest, members of the media and legal observers.
Post-Dispatch reporter Mike Faulk was one of those arrested. He said police yelled at him to "move back, move back," before officers knocked him to the ground. He said a foot pushed his head into the pavement before an officer used pepper spray on his face. He was arrested and released on $50 bond the next day.
Another woman who was arrested, Dellicia Jones, said the officers were advancing on the crowd, banging their batons on the ground.
"When we tried to walk one way, they came at us with pepper spray and batons and told us to go the other way," she said, but there was no other place for them to go.
Jones said that though she wasn't treated roughly by officers, she saw others who were.
"It was nowhere near right, at all," she said.
Each of the three days of protests before the kettling incident started peacefully, police said, but later, demonstrators became more violent. On one night, a group surrounded the house of St. Louis Mayor Lyda Krewson, with some throwing objects and paint at the home and breaking windows.
At least nine police officers were injured in the confrontations, including one who had a dislocated shoulder and another with a broken jaw.
The ACLU said, though, that police didn't observe protocol when using what it described as "chemical weapons" against protesters.
"While long shifts and being the subject of the protest is understandably challenging for police, that is no excuse for violating the Constitution," said Tony Rothert, legal director of the ACLU of Missouri.