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New charges were added against the three men accused of hurling large rocks at cars west of Denver last month, killing a 20-year-old woman, including attempted first-degree murder, assault and attempted assault.

Joseph Koenig, Nicholas “Mitch” Karol-Chik and Zachary Kwak, all 18, now each face 13 charges, including first-degree murder, in the rock-throwing spree April 19, court records show. The three men are accused of throwing large landscaping rocks at cars, one of which smashed through Alexa Bartell’s window, striking her in the head and killing her.

From left, Zachary Kwak, Nicholas “Mitch” Karol-Chik, and Joseph Koenig were arrested on suspicion of first-degree murder with extreme indifference after authorities say they threw a large rock at Alexa Bartell’s car, killing her April 19. (Photos provided by Jefferson County Sheriff’s Office)

The charges include one count of first-degree murder with extreme indifference, six counts of attempted first-degree murder, three counts of second-degree assault and three counts of attempted second-degree assault, records show. The extreme indifference charge alleges the men knowingly created a “grave risk of death,” without caring who was injured or killed, resulting in Bartell’s death.

Bartell’s car was the last car struck in a series April 19, investigators say, as the three men allegedly threw rocks from a pickup at oncoming traffic. Authorities say the men hit six other cars and two other drivers were injured.

When investigators found Bartell’s car, there was a large hole in the front windshield on the driver’s side and the rear window was completely broken out. After their arrests, the men told investigators that they returned to the crash site to take a picture of the car to serve as a memento, according to arrest affidavits. 

During interviews with police, two men accused each other of throwing the rock that killed Bartell. Karol-Chik said Kwak threw the rock while she was driving on Indiana Street at about 10:45 p.m. Kwak said Koenig threw it. Koenig refused to be interviewed by police. 

Last week a judge ordered the three men be held without bond. Their attorneys waived a reading of the charges in court Wednesday afternoon and a judge set a motions hearing for May 16.

CORRECTION: This story was updated at noon Wednesday, May 3, 2023, to clarify the definition of first-degree murder with extreme indifference.

Olivia Prentzel

Olivia Prentzel is a general assignment writer for The Colorado Sun. Email: