Participant in Colorado rock-throwing spree seeks reduced prison sentence

Shelly Bradbury, The Denver Post on Sep 9, 2025

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DENVER — One of the three men convicted in the killing of 20-year-old Alexa Bartell during a spree of rock-throwing attacks in Jefferson County more than two years ago asked the judge to reduce his prison sentence this month.

Nicholas “Mitch” Karol-Chik was sentenced in May to 45 years in prison for the death of Bartell, who was killed April 19, 2023, when Karol-Chik and two other teenagers threw a 9.3-pound rock through her windshield as she drove on Indiana Street near the Rocky Flats National Wildlife Refuge. The rock struck Bartell in the head.

Karol-Chik asked First Judicial District Court Judge Christopher Zenisek to reduce his sentence from 45 to 35 years in prison, the lowest possible sentence he could serve under the terms of his plea agreement.

Karol-Chik, 20, has heavily participated in programs and jobs since his incarceration, his attorney, Holly Gummerson, wrote in the Sept. 4 motion to reconsider the sentence.

He is using his time in prison in a productive manner and has applied to a 10-year prison education program in which he would receive a bachelor’s degree in Christian studies and counseling and then complete six years of field work in chaplain’s offices across the prison system, she wrote in the motion.

He has not had any disciplinary incidents so far during his incarceration, she wrote.

“Mr. Karol-Chik is not a young man who will continue to wreak havoc in our community,” she wrote. “He is a young man who wants to give back, right his wrongs and serve his community in any way possible.”

Brionna Boatright, spokeswoman for the First Judicial District Attorney’s Office, said prosecutors will object to any sentence reduction.

Gummerson noted that Karol-Chik received a longer prison sentence than one of the other men involved in the attacks. Zachary Kwak, 20, was convicted of assault and attempted assault and sentenced to 32 years in prison, the maximum possible sentence.

Karol-Chik was convicted of second-degree murder and attempted first-degree murder. He faced between 35 and 72 years in prison under the terms of his plea agreement.

A third participant in the rock-throwing spree, Joseph Koenig, 20, was convicted of first-degree murder in a jury trial and sentenced to life in prison.

The trio were each 18 on the night they killed Bartell. They’d thrown rocks at several other cars that night, starting with parked cars and escalating to throwing rocks into passing cars.

The teenagers, riding together in a truck, egged each other on, cheering when the rocks hit cars and caused damage. The driver of the truck sped up before the attacks, and Koenig whooped with excitement after Bartell was killed and her car drifted off the road, testimony at trial revealed.

Prosecutors argued during Koenig’s jury trial that he threw the rock that killed Bartell; his defense attorneys argued that Kwak threw it. Both sides acknowledged that all three teenagers could be convicted in Bartell’s killing regardless of who threw the rock.

Karol-Chik and Kwak both pleaded guilty and agreed to testify against Koenig during his jury trial.

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