Jefferson County sheriff’s investigators, relying on cellphone tracking, identified and arrested three 18-year-old high school friends from Arvada in the rock-throwing death of 20-year-old Alexa Bartell.
The investigators made the arrests late Tuesday and early Wednesday at Arvada homes where the three lived with their parents and took the three into custody. The suspects — Joseph Koenig, Nicholas “Mitch” Karol-Chik and Zachary Kwak — were being held in the Jefferson County jail without bond.
Jefferson County authorities said each will face a charge of first-degree murder with extreme indifference and will be advised of the charges in court Thursday.
All three are suspected of throwing rocks at drivers in a crime spree last week that targeted seven different victims — including Bartell, who was killed when a rock crashed through the window of her yellow Chevy Spark and hit her while she was talking on her phone with a friend.
Additional charges likely will be filed, pending determinations by the First Judicial District Attorney’s Office, authorities said Wednesday.
“The suspects went from place to place, throwing large rocks through the windshields of moving vehicles. We have not seen that before,” sheriff’s office spokeswoman Jacki Kelley said. “This was a beautiful young woman with her whole life in front of her who was simply driving home.”
A suspect vehicle also has been identified — a black 2016 Chevy Silverado, authorities said. It remains unclear who was driving during the rock-throwing spree last week, but Kelley said investigators believe all three suspects threw rocks.
The suspects are friends who lived in separate homes with their families.
Koenig attends Ralston Valley High School and Kwak attends Standley Lake High School, according to Jeffco Public Schools. Koenig, who transferred into the school district from another state in August 2018, was enrolled, concurrently, in the Jeffco Virtual Academy until July 2022. Kwak, who transferred to Standley from another state in August 2021, concurrently attends Warren Tech, a career and technical education program in the district.
Karol-Chik is enrolled in Jeffco Virtual Academy; he attended Ralston Valley High until May 2022.
The suspects “will not be returning to school, per district policy,” the school district said in a statement. “We will continue to follow school and district protocols, and law enforcement guidance.”
Mental health support staff with the district is available for students who are having a challenge processing the information about the suspects’ arrests and the accusations, district officials said.
As police were at Koenig’s house making that arrest, Koenig’s father, Mark Edward Koenig, “obstructed our ability to make an arrest of his son,” Kelley said.
The father also was arrested for allegedly obstructing deputies and was taken to jail.
Bartell was killed as she was driving northbound in the 10600 block of Indiana Street at about 10:45 p.m. on April 19. Her Chevy Spark was hit by “large landscaping rocks,” authorities said, in a spree that began shortly after 10 p.m. that night in Westminster.
Two drivers injured in the other attacks suffered minor injuries. Seven vehicles were damaged.
Making the arrests means “we have a safer community this morning,” Kelley said. “We were concerned this was a crime that could potentially happen again.”
Jefferson County sheriff’s investigators worked with Westminster police, Arvada police and the Boulder County Sheriff’s Office to identify and arrest the suspects. The investigators relied primarily on “mobile-device forensics,” involving cellphone towers, to identify and find the suspects, Kelley said.
Police officers also received more than 300 tips from the public that provided “supporting information” that helped in catching the suspects.
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