STEM shooter found guilty of first-degree murder

After five hours of deliberation, jurors found Devon Erickson guilty of first-degree murder for his role in the attack on STEM School Highlands Ranch on May 7, 2019.

Erickson faces a mandatory sentence of life in jail with no chance of parole. He will be sentenced on Sept. 17 following a presentence investigation. 

In addition to two counts of first-degree murder, the jury found Erickson guilty of 44 other charges, including attempted first-degree murder, possession of a weapon on school grounds and reckless endangerment.

Emotions rippled across the courtroom as Douglas County District Court Judge Theresa Slade read the verdicts. From the victims' side, people nodded in approval and patted each other on the back.  One young woman on the defendant's side was sobbing.  Erickson's father took notes on the proceedings.

Victims and their families,  and Erickson's family listened intently to each verdict. 

Erickson, wearing a grey suit and tie, stared ahead with his hands folded in front of him. He did not have a visible reaction to the verdicts.

During the 12 day trial, the jury heard from 63 witnesses, only two of whom were called by the defense. The prosecution called on STEM students and teachers, doctors, forensic experts, first responders and others to share their insights into what happened that day.

Alec McKinney, who pleaded guilty in 2020 to charges similar to Erickson’s, also testified for the prosecution. McKinney told the jury that the two of them had an elaborate plan for the attack that included killing everyone in Room 107 and then Erickson killing McKinney so he could “come off as the hero.”

The 2019 attack left eight students injured and one student, Kendrick Castillo, dead. Castillo was fatally shot as he and several other students stormed Erickson to disarm him.

“The only reason everybody in that room isn’t dead … is heroes," lead prosecutor George Brauchler said in his closing argument, referring to Castillo and the other students who rushed Erickson.

Physical evidence discussed during the trial showed that Erickson’s gun had been fired four times, hitting three students. McKinney shot nine bullets, injuring four students.

The defense attempted to persuade the jury that Erickson was an unwilling participant in the shooting. They claimed in closing arguments that Erickson had some responsibility for what happened but that it wasn’t his intent to kill anyone. Defense attorney David Kaplan reminded the jury before their deliberations that they could find Erickson guilty of lesser charges, including second-degree murder, reckless manslaughter and criminally negligent homicide.

“Devon didn’t go in there with some plan,” Kaplan said.

The two expert witnesses called by the defense spoke about the possibility that Erickson had accidentally fired his gun due to an involuntary muscle contraction and that he was impaired because of long term cocaine use and lack of sleep.

The prosecution repeatedly questioned these ideas by asking witnesses if Erickson was coherent earlier in that day and in the moments before the shooting. They also drew attention to the fact that there are no academic studies available that cite involuntary muscle contractions for multiple gunshots.

MORE: Full coverage of the STEM shooting and trial