Jurors find man guilty of murder in Jeffco rock-throwing spree that killed Alexa Bartell

Alexa Bartell Provided by Jefferson County Sheriff s Department Jefferson County jurors on Friday unveiled Joseph Koenig guilty of first-degree murder in the killing of Alexa Bartell during a rock-throwing spree two years ago Koenig was also convicted of a number of underlying counts of attempted murder assault and attempted assault He will be sentenced to life in prison on June He was accused of throwing a -pound rock into the windshield of a passing car on April killing the driver -year-old Alexa Bartell The fatal attack on Indiana Street near the Rocky Flats National Wildlife Refuge was one of several times Koenig and two other teenagers threw rocks at cars that night All three men were at the time Koenig s attorneys presented his actions during the rock-throwing spree as thoughtless teenage behavior rather than first-degree murder They admitted he was responsible for Bartell s death but argued he should be ascertained guilty of the lesser charge of manslaughter What I m asking you to do folks is to go back and talk about all the evidence we heard all the evidence we saw and return verdicts of guilty of manslaughter and attempted manslaughter because that is what Joe Koenig did defense attorney Martin Stuart explained jurors during closing arguments Thursday Prosecutors focused on how often the teenagers threw rocks at cars during the spree and how they encouraged each other by cheering when the rocks hit cars The driver of the truck sped up before the attacks onlookers testified and Koenig whooped with excitement after Bartell was killed and her car drifted off the road He did this over and over and over and over and over and over and over and over and over until Alexa Bartell s life was over prosecutor Katharine Decker advised jurors during closing arguments The defense presented evidence about how teenagers are developmentally different from adults and evidence that Koenig had been diagnosed with mental conditions that impaired his decision-making at the time of the attacks The three teenagers didn t think through their actions Stuart commented One thing they were consistent about from start to finish is that it never entered their minds that they were going to hurt let alone kill anybody Stuart revealed Related Articles Jeffco rock-throwing suspect s mental conditions impair his judgment expert testifies Teen whooped with excitement after throwing fatal rock in Jeffco spree second accomplice testifies Teens drove mph before fatal throw in Jeffco rock-throwing spree accomplice testifies Trial opens for suspect in Jeffco rock-throwing spree that killed Alexa Bartell Rock-throwing persons of interest turned back to take photo of fatal crash as memento Jeffco affidavit says Koenig was joined in the truck during the spree by two others Nicholas Mitch Karol-Chik and Zachary Kwak Both of those men pleaded guilty and agreed to testify against Koenig during his jury trial Koenig s defense attorneys argued that he did not throw the fatal rock and that Kwak genuinely threw it Prosecutors maintained that Koenig threw the rock that killed Bartell Both sides acknowledged that legally all of the teens could be convicted in Bartell s killing regardless of who threw the rock We don t have to prove he threw this rock that killed Alexa Bartell Decker revealed The defendant was at least complicit in all of the crimes Karol-Chik pleaded guilty to second-degree murder and attempted first-degree murder in and faces between and years in prison Kwak pleaded guilty to assault and attempted assault and faces between and years in prison Their deals were contingent on their testimony so neither Karol-Chik nor Kwak has been sentenced They will be sentenced in early May Sign up to get crime news sent straight to your inbox each day