Prosecutors in Portland, Oregon, have declined to charge a conservative journalist whose arrest while documenting protests outside of the city’s immigration detention center had angered President Trump.

The Multnomah County District Attorney’s Office declined Monday to charge Nick Sortor with disorderly conduct. He was arrested last week during the nightly protests outside the U.S. Immigration and Customs Enforcement’s holding facility.

Court documents referenced Mr. Sortor’s video footage showing protesters confronting him on Oct. 2 after he recorded and shined a light on them.

One protester used an umbrella to push him and Mr. Sortor responded by yanking the umbrella out of the woman’s hands, the court documents say. Protesters then surrounded Mr. Sortor, who tried to fend off the group but was pushed down while trying to run away.

Prosecutors said police took note of the “scrum” and arrested three people, including Mr. Sortor. He spent the night in jail and was released the following day.

The district attorney’s office described Mr. Sortor’s actions as “defensive in nature” and “reasonable under the circumstances.”

“Sortor’s conduct of attempting to video record and shine a bright light at the other side, while certainly provocative, is not criminal and does not give rise to any legally justifiable ability to respond with force,” prosecutors wrote in a memo declining to pursue charges.

Officials said the other two persons arrested with Mr. Sortor will be charged.

News of Mr. Sortor’s arrest reached Mr. Trump, who considered pulling federal funding from Portland in response.

“We will not fund states that allow anarchy,” White House spokeswoman Karoline Leavitt said last week. “There will also be an additional surge of federal resources to Portland immediately, including enhanced [Customs and Border Patrol] and ICE resources.”

“Instead of arresting these violent mob members night after night after night who are ravaging this community, the police arrested a journalist who was there trying to document the chaos, and everyone in this room should be extremely concerned about that,” Ms. Leavitt added.

She also confirmed that the Department of Justice has contacted Mr. Sortor and will launch an investigation into his arrest.

• Matt Delaney can be reached at mdelaney@washingtontimes.com.