nytimes June 16, 2021 10:00pm Man, 20, Is Found Guilty in Colorado School Shooting #schoolshootingsandarmedattacks #massshootings #castillokendrickd2019 #ericksondevon #stemschoolhighlandsranchhighlandsranchcolo #colorado #douglascountycolo #alecmckinney #decisionsandverdicts #murdersattemptedmurdersandhomicides #news Man, 20, Is Found Guilty in Colorado School Shooting Devon Erickson was one of two students who planned and carried out an attack at the STEM School Highlands Ranch in which one student was killed and eight others were injured on May 7, 2019.