A 24-year-old man who hit another man over the head with a baton in June during dueling downtown Portland demonstrations was sentenced Friday to nearly six years in prison.

Gage Halupowski pleaded guilty to second-degree assault in connection with the June 29 attack on Adam Kelly outside The Nines Hotel along Southwest Morrison Street. Halupowski was identified as one of several masked, black-clothed demonstrators seen on video hitting and pepper-spraying Kelly after he appeared to come to the aid of another man who’d been attacked during the protests, authorities said.

Kelly, a right-wing protestor at the demonstrations, wrote on Facebook at the time that the blows to his head led to him suffering a concussion and needing 25 staples to close the wounds.

Multnomah County Deputy District Attorney Melissa Marrero said Halupowski hitting Kelly in the back of the head with an expandable baton was “completely unexplainable, completely avoidable and didn’t need to happen.”

She said Kelly and Halupowski both were lucky that Kelly survived his injuries.

Defense attorney Edward Kroll said Halupowski made “a really terrible decision” and that Kelly didn’t deserve what happened to him, but the attorney believed the agreed-upon 70-month prison sentence was “one of the harshest sentences I’ve seen for someone with no criminal background and young age.”

Kroll cited the Measure 11 charges Halupowski faced and the attack being caught on video as leaving the 24-year-old with few options other than taking the plea deal. Kroll also noted that Halupowski hit Kelly once, but it had been determined that at least two other people hit him in the head with batons.

Marrero disagreed with Kroll’s assertions, saying she felt the charges and sentence were appropriate based on the severity of Kelly’s injuries and Halupowski’s strike. She said first-degree assault, which carried a potential 90-month sentence, and riot charges were initially considered in the case.

The prosecutor also said another person has been indicted and more people are under investigation in the same attack and other incidents stemming from the June demonstrations.

“My office has individuals charged on both sides of the political spectrum,” Marrero said. “We are not picking sides based on political affiliation, political views or anything like that.”

Halupowski didn’t give any statements while in court Friday. Kelly sat in the gallery behind him. His bald head bore several scars. He declined to comment after the court hearing.

Halupowski was one of three people arrested during rival demonstrations between far-right and anti-fascist groups on June 23. Police at one point declared the protests a civil disturbance.

At least eight people were injured, including three police officers and conservative writer Andy Ngo.

The two other people arrested, James Stocks and Maria Dehart, were charged with harassment and disorderly conduct. Stocks, 21, pleaded no contest to harassment and was sentenced Tuesday to one year of probation and 50 hours of community service. He admitted to throwing a milkshake at a group of right-wing supporters.

Dehart, 23, has pleaded not guilty to her charges and is scheduled to next appear in court on Nov. 13, court records show.

Additional charges of unlawful use of a weapon, attempted assault of a public safety officer and interfering with a peace officer were dropped as part of Halupowski’s plea deal.

Court documents show that a Portland police officer saw Halupowski hit Kelly, followed him and pointed him out to other officers who helped arrest him. He was accused of punching another officer in the arm while being taken into custody.

-- Everton Bailey Jr.

ebailey@oregonian.com | 503-221-8343 | @EvertonBailey

Visit subscription.oregonlive.com/newsletters to get Oregonian/OregonLive journalism delivered to your email inbox.