Police walk through a haze as they clash with protesters in Ferguson, Mo., in August 2014. (Jeff Roberson/AP)

The city of Ferguson, Mo., on Tuesday became the target of a federal lawsuit filed on behalf of four people arrested during the 2014 unrest in the St. Louis suburb.

The 31-page suit lawsuit, filed in U.S. District Court in Missouri, seeks $20 million in damages and alleges malicious prosecution and violations of the protesters’ rights. In it, the four plaintiffs claim that their 2014 arrests violated their rights and led to court cases that were carried out without evidence.

The four plaintiffs — Michael Powers, Jasmine Woods, Michael Lhotak and Keith Rose — were taken into custody in the days following the death of Michael Brown, a black teenager who was fatally shot by a police officer in August 2014.

Brown’s death stirred unrest in the St. Louis area and nationwide as many questioned the use of force and police tactics — a debate that is ongoing.

Also named as defendants in the lawsuit were prosecutors Stephanie Karr and J. Patrick Chassaing, as well as Ferguson police officers. It was filed by the nonprofit Arch City Defenders and Dowd & Dowd, a law firm.

“People have said, ‘What’s changed?'” Michael-John Voss of Arch City Defenders told The Washington Post on Tuesday. “Some things have changed, and a lot still has to be done.”

A Ferguson spokesman said on Tuesday afternoon that officials hadn’t had a chance to review the lawsuit, so they could not comment on it.

Woods, Lhotak and Rose were taken into custody amid a peaceful demonstration on Aug. 11, 2014, according to the lawsuit. Powers was arrested a few days later.

The plaintiffs, the lawsuit states, “suffered damages including the loss of their liberty, as well as fear, anxiety and emotional distress.” All were acquitted of the charges they faced.

“As in the other ‘failure to comply’ cases pursued by Defendants, at no time during the investigatory process or in the subsequent criminal prosecution of Plaintiffs did the Defendants ever have any evidence that Plaintiffs engaged in criminal conduct,” the lawsuit states. “Nevertheless, Defendants arrested Plaintiffs, held them in jail for 24 hours, and pursued criminal charges against Plaintiffs up to and including trial, without any probable cause to do so, based solely on the fact that Plaintiffs had been arrested.”

In the suit, the plaintiffs allege that their court cases were intended to suppress free speech. Cited in the court documents is a St. Louis Post-Dispatch report in which Chassaing was quoted as saying that the cases against three of the plaintiffs “were pursued in order to deter others participating in future protests from assuming there are no limits or parameters to their activities.”

It also claims that Karr and Chassaing, who worked as prosecutors, had financial reasons to move forward with the proceedings.

Reports the Post-Dispatch:

A Post-Dispatch story in May highlighted how private lawyers from the firm Curtis, Heinz, Garrett and O’Keefe billed Ferguson tens of thousands of dollars for prosecuting the cases.

The article also noted that the defendants had all been charged with “failure to comply.” It’s often referred to as a “contempt-of-cop” charge, and one the U.S. Department of Justice has accused Ferguson police of routinely abusing.

The lawsuit, filed on the second anniversary of Brown’s death at the hands of then-Ferguson police officer Darren Wilson, alleges that financial pressures put on Karr and Chassaing by their firm drove their actions.

Emails sent to Karr, who the Post-Dispatch notes had previously served as city attorney and prosecutor, and Chassaing seeking comments had received no response as of Wednesday morning.

Voss said that lawyers are still looking for other people who were arrested and that the lawsuit could be amended to include more names.

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