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Teens charged in deadly rock-throwing spree that killed Alexa Bartell will face trial

Teen suspects Joseph Koenig, Nicholas “Mitch” Karol-Chik and Zachary Kwak were arrested on charges of first-degree murder, attempted first-degree murder among other charges one week after the crime.
Posted: 2:54 PM, Oct 18, 2023
Updated: 2023-11-27 16:11:29-05
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Alexa Bartel car hit by rock

JEFFERSON COUNTY, Colo. — The three suspects charged with murder in a rock-throwing spree that allegedly killed a young Jefferson County woman while driving her vehicle back in April will go to trial after a judge ruled sufficient evidence had been presented during a preliminary hearing Wednesday.

An arraignment date was not set as both sides will next determine if the suspects will be tried together or separately.

Judge Christopher Zenisek ruled all counts will be bound over for arraignment, including multiple counts of assault and attempted murder connected to a slew of rock-throwing in incidents that happened on April 19.

Alexa Bartell, 20, of Arvada, was driving northbound on Indiana Street on April 19 when at around 10:45 p.m., a large rock was thrown at her car, crashing through her front windshield.

Teen suspects Joseph Koenig, Nicholas “Mitch” Karol-Chik and Zachary Kwak were arrested on charges of first-degree murder, attempted first-degree murder, second-degree assault and attempted second-degree assault one week after the crime.

The initial preliminary hearing on September 8 was postponed after the lawyer for Joseph Koenig argued the defense team had not had enough time to evaluate some evidence, specifically OnStar and cell phone records provided by the prosecution.


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Koenig’s team added that they had retained an expert to evaluate the data but needed more time to review because of its complexity and that it was in a format that they said could not be viewed without specialized software.

The additional data is tied torecently added charges against two of the suspects in an alleged throwing incident on April 1, two weeks before Alexa Bartell, 21, was killed.

The cell phone tracking data provided by major carriers is key evidence that helped Jefferson County investigators identify if any phone numbers were in the vicinity of several of the rock-throwing incidents.

Along with the incident that killed Bartell, there were 6 other rock-throwing incidents with some injuries reported.As its first and only witness, the People called the lead investigator on the case, Detective Dan Manka with the Jefferson County Sheriff’s office. Manka explained how that retrieved cell phone data began to piece together a timeline and potential suspects.“We determined there were 11 numbers in common with all four locations,” testified Manka.

He was referring to four of the 7 reported rock-throwing incidents that night, including the fatal one that allegedly struck Bartell.

From there, Manka said investigators were able to isolate a single cell phone number that was later connected to suspect Koenig’s mother.“Advanced timing data placed him in the vicinity of the event,” said Manka, who also testified the phone number returned to the scene where Bartell’s vehicle was two times.

Detective Manka also revealed investigators obtained surveillance video from a camera on Coalton Road near a Boulder County park which they believed connected the suspects’ truck to one of the rock-throwing incidents.Manka testified about the sequence of events in the video which was previously referenced in the arrest affidavit which stated the drivers of two vehicles traveling south on McCaslin Road suddenly hit their brakes and turned on their hazard lights. The only other vehicle on the road at that same time appeared to be traveling north and speeding off in the opposite direction.

Affidavit: Rock-throwing suspects returned to JeffCo fatal crash to take photo

After news reports of the incident, investigators received over 300 tips from the public. During cross-examination of Detective Manka, the defense for the suspects argued that there were other reports of alleged rock-throwing incidents that investigators learned about but did not pursue, including a report of an alleged incident on westbound I-70 near Sheridan Blvd. another along W. 93rd Avenue in Arvada.

Landscaping rocks from several of the crime scenes were collected by investigators and presented by the People as evidence during the hearing, but the defense pointed to the fact that no DNA was found linking the rocks to the suspects.

In the affidavit, it was revealed that one of the rocks discovered in a victim’s vehicle, not Bartell’s, did have “two contributor DNA sample identified on the rock that was suitable for comparison,”

Corroborating the cell phone data, Detective Manka testified that a tipster came forward after seeing news reports of Bartell’s death, revealing to a Westminster Police investigator that the tipster had a conversation with a coworker that "he felt was related and wanted to report it," said Manka.

Alexa Bartel car hit by rock

That information was also revealed in the affidavit in which the tipster said the coworker, identified hereafter as Witness 1, told him on April 19, he had seen a person named “Joe” and “Mitch” plus a third person loading rocks into their vehicle from a Walmart parking lot. Witness 1 told the trio to “take him home because he did not want anything to do with what they were up to,” according to the affidavit.

Investigators then met with Witness 1 who said he was a former coworker of Koenig and reportedly received a call through social media on the evening of April 19 in which the suspect asked if the witness wanted to hang out, according to the affidavit.

Alexa Bartel car hit by rock

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On the stand Wednesday, Detective Manka said that witness revealed that before the rock-throwing incidents, he had driven around in the truck and eventually went to a Walmart. During that trip, the witness said he went to the bathroom and when he came out, he said he saw Koenig, Karol-Chik and Kwak picking up landscaping rocks from the Walmart parking lot and placing in the truck, the affidavit stated.

Manka testified that it was at that point Witness 1 told the others that he "felt a bad feeling and wanted to be taken home." During a search, investigators determined a 2016 Chevrolet Silverado truck was registered to a person believed to be Karol-Chik's mother and later drove to the home and located the truck, according to the affidavit.

After a search warrant was executed and the truck was seized, Detective Manka said a landscaping rock was discovered in the back seat of the truck.

On the evening of April 25, nearly a week after Bartell's death, Jefferson County deputies took Karol-Chik into custody and overnight he was interviewed by investigators. Detective Manka testified during the course of that interview, he allegedly identified Kwak as another person in the truck. Manka described Karol-Chik's initial demeanor during the interview as "dismissive" and initially denied, but during the course of the interview "did admit to participation" and that he was concerned that he "did something that will ruin the rest of his life,"

The arrest affidavit also revealed that Karol-Chik said they all got excited when they’d hit a car. He said Kwak was the one who threw the rock that hit Bartell’s vehicle, the affidavit reads. He told investigators that Koenig slowed the vehicle afterward, turned back around to let Kwak take a photo of Bartell's damaged vehicle, which had traveled off the roadway into a field.

During that intervew, Karol-Chik said he “felt a hint of guilt,” according to the affidavit.

Rock-throwing suspects went back to scene of JeffCo fatal crash to keep photo as a memento

The defense argued in Wednesday's preliminary hearing, and the People agreed, that it was not clear who in the truck threw the rocks during the alleged spree.

Detective Manka testified that the day after the rock-throwing incidents, the three suspects met at a restaurant to allegedly solidify their stories in case they were confronted by authorities reportedly stating that "they were blood brothers and that nobody could talk about this."

Despite Karol-Chik's allegation that Kwak took a photo of Bartell's vehicle, Detective Manka testified that no image had been found on Kwak's phone but there had "been indications of an image that had been deleted" near the time of Bartell's death. He also said there was an application log that showed Kwak's camera app was opened at around 10:48 p.m., near the time of the Bartell incident.

On cross-examination of Detective Manka, defense attorneys pressed him as to why investigators did not search for Event Data Recorder (EDR) data typically available on vehicles that would often reveal the speed of travel.

Defense also asked why speed data from other sources like cell phones with GPS or Progressive Snapshot were not obtained from the victim vehicles.

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Defense again pointed out that there was no physical evidence as to which of the three suspects threw the rocks and that two of the suspects pointed fingers at each other as to which allegedly threw the rock that killed Bartell.

"You cannot say who threw which rock at any of the victims in this case?" a defense laywer questioned Manka who replied: "I cannot."

The only DNA found on the landscaping rock located near Bartell's vehicle was that of Bartell, not the suspects.

Kwak, in his statements to investigators denied "throwing any single rock" a defense attorney said who also stated during the hearing Kwak denied all involvement except for being in the truck and passing rocks to the other suspects.


The following from the arrest affidavit details the 6 other rock-throwing incidents that happened the night Alexa Bartell was killed. This information was also presented by the People in Wednesday's preliminary hearing.

  • Driver 1 behind the wheel of a Subaru was attempting to turn on to Indiana street when he saw what he described as a light-colored SUV or truck approach his vehicle heading in the opposite direction. He said he saw a large rock launched from the other vehicle, which crashed through his windshield and struck him in the shoulder, according to the affidavit. That landscaping rock was found on the front seat of the vehicle and later analyzed by a crime lab.
  • Driver 2 was traveling just behind Driver 1 when he stated he saw the vehicle in front of him swerve and then felt "an object" hit the front of his car.
  • At around 10 p.m., Driver 3 was headed westbound on W. 100th Avenue near Simms Street when he stated he saw someone in an eastbound vehicle throw a rock at his car, shattering the windshield, the affidavit read. Driver 3 had minor injuries.
  • Driver 4 was traveling southbound on Highway 93 near State Highway 72 when her windshield was also struck by a rock, according to investigators. Driver 4 said she didn’t see any other vehicles and had minor injuries on her face.
  • At 10:15 p.m., Driver 5 was headed south on Highway 93 near State Highway 128 when the rear and driver’s side windows of his vehicle were broken by what he described as an unknown object. According to the affidavit, Driver 5 first thought his vehicle might have been hit by flying debris due to the winds. He did not report seeing any other vehicles in the opposite lane or on the side of the road.
  • Driver 6 was traveling south on Highway 93 near State Highway 128 behind Driver 5’s vehicle. In the affidavit, Driver 6 said at about 10:30 p.m., a northbound truck passed him, “debris hit and cracked his windshield and damaged his car.”

This is a developing story and will be updated.

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