Four journalists covering a protest on Highway 40 in St. Louis were arrested Tuesday (Oct. 3), according to U.S. Press Freedom Tracker.

About two weeks earlier on Sept. 17, St. Louis police arrested three journalists covering a protest in downtown.

In both cases, the protests were over the acquittal of Jason Stockley, a white former St. Louis police officer who in 2011 fatally shot Anthony Lamar Smith, a black man.

Also in both cases, those arrested describe being caught in a police "kettle" in which police ordered everyone to sit down and then arrested them. In the downtown protest, one of the journalists reported that police surrounded from all four sides, ordered the crowd to disperse, but blocked the exits. Many, including the journalists, were pepper-sprayed. Some report being knocked down and jabbed, and some incidents were caught on video.

Journalists reported being held in jail from 12 to 20 hours before being released.

Police charged journalists in the Sept. 17 incident with failure to disperse, according to the reports by U.S. Press Freedom Tracker. A photographer arrested Oct. 3 said he saw a document that listed the charge as "trespassing." 

Many said they were wearing press credentials and told officers they were covering the events.

(Also read: When a journalist is arrested covering a protest, what should the news outlet do?)

Those arrested included:

Getty photographer Scott Olson (Sept. 17)

Independent livestreamer Jon Ziegler (he was arrested at both protests, Sept. 17 and Oct. 3)

St. Lois Post-Dispatch reporter Mike Faulk (Sept. 17)

Freelance photographer Daniel Shular (Oct. 3)

Ty Bayliss, a cameraman and editor for the progressive online news organization The Young Turks (Oct. 3)

Jordan Chariton, a reporter for The Young Turks (Oct. 3)

U.S. Press Freedom Tracker began documenting arrests of journalists in the United States earlier this year, along with equipment searches and seizures and physical attacks on journalists. Read about their efforts.