ST. LOUIS (AP) — Four journalists arrested during last summer’s Ferguson protests over the shooting death of Michael Brown filed a federal lawsuit Monday against St. Louis County police and 20 of its officers, accusing them of violating the reporters’ civil rights and unjustifiably detaining them.

The lawsuit, filed Monday in St. Louis, alleges the arrests for the journalists’ failure to disperse as demanded by police on Aug. 18 and Aug. 19 were “undertaken with the intention of obstructing, chilling, deterring, and retaliating against (the) plaintiffs for engaging in constitutionally protected speech, newsgathering and recording of police activities.”

The plaintiffs include Ryan Devereaux of The Intercept online investigative publication, as well as Ansgar Graw – a correspondent with the conservative German daily Die Welt – and reporter Frank Herrmann, who writes for German regional papers. The other plaintiff is freelance journalist Lukas Hermsmeier.

The lawsuit, which identifies the journalists as U.S. citizens and says they spent hours in custody, seeks unspecified damages and a court order barring county police from future alleged infringements of media access “to policing activities.”

Peter Krane, the county counselor, said Monday he had not seen the lawsuit and deferred discussing it publicly until he had an opportunity to do so.

The journalists’ arrests on charges that as of Monday remained unresolved took place during often-violent protests that followed the Aug. 9 death of Brown, a black, unarmed 18-year-old shot and killed by Ferguson police officer Darren Wilson, who is white, during a confrontation.

A St. Louis County grand jury and the U.S. Department of Justice later cleared Wilson of wrongdoing, though he resigned from the department in November.

The four journalists pressing Monday’s lawsuit were among at least 10 arrested or detained while covering Ferguson protests in the immediate aftermath of Brown’s death. Capt. Ron Johnson of the Missouri State Highway Patrol, while heading security in Ferguson, said at the time that law enforcers had difficulty discerning journalist from activist.

“In the midst of chaos, when officers are running around, we’re not sure who’s a journalist and who’s not,” Johnson said at the time, when The Associated Press and dozens of other American media organizations sent a letter to law enforcement officials in Ferguson, criticizing the treatment of reporters.

Devereaux and Hermsmeier claim in the lawsuit they were wrongly arrested and hit by police-fired rubber bullets after showing officers their media credentials. Graw and Herrmann claim they were taken into custody while wearing press badges around their necks and carrying still cameras.

Monday’s lawsuit came four days after county police, their St. Louis city counterparts and the Missouri State Highway Patrol settled a federal lawsuit pressed by six Ferguson protesters, agreeing to restrict law enforcement use of tear gas and other chemical agents on crowds.