STEM School shooter sentenced to life in prison without parole plus hundreds of extra years

In a file photo, STEM School Highlands Ranch shooter Devon Erickson is seen making an appearance at the Douglas County Courthouse May 15, 2019, in Castle Rock.

Pool photo by Joe Amon/The Denver Post

A man previously convicted of first-degree murder in the deadly 2019 shooting at STEM School Highlands Ranch was given two sentences of life in prison without a possibility of parole Friday plus hundreds of additional years.

Prosecutors later calculated the total sentence as 1,282.5 years in addition to life in prison without parole.

The sentencing of Devon Erickson by District Judge Theresa Slade in a Castle Rock courtroom followed a five-hour hearing in which several people  impacted by the deadly attack told the judge how that day changed their lives forever. The family of the shooter pleaded for leniency for someone they say they will always love.

Erickson, 20, was found guilty of first-degree murder earlier this summer for his role in the May 7, 2019, shooting which left student Kendrick Castillo dead after he confronted the killers. Eight other students were injured.

Erickson was also found guilty of 44 other charges, including 31 counts of attempted first-degree murder. 

“There’s evil in the world, people who want to try to hurt and harm,” said John Castillo, Kendrick’s father, during the hearing. “That's what this was.”

Castillo was fatally shot as he and several other students stormed Erickson to disarm him, according to testimony during the trial.

Another participant in the shooting, Alec McKinney, who pleaded guilty to dozens of charges in 2020, was sentenced last year to life in prison but could eventually be eligible for parole because he was a juvenile — age 16 — at the time of the crime. Erickson was 18 at the time.

Victim impact statements

During Friday's sentencing hearing, those who shared details about their lives since the attack spoke of crippling anxiety, a constant struggle with falling asleep at night, flashbacks and other symptoms caused by the trauma. 

Many said they constantly fear the incident will be repeated and that they find themselves looking for active shooters in their daily lives. Some said they have panic attacks triggered by loud noises and enclosed spaces, and some are working through deeply-rooted struggles with trust. Others said they will carry wounds from the attack the rest of their lives.

“There is no describing the terror I still experience to this day when I encounter a flashback, hear a sudden loud noise or even when I wake up from a nightmare,” said Lauren Harper, the teacher in the school's Room 107, where the shooting took place. “I still often have nightmares of that exact moment.”

MORE: Full coverage of the STEM shooting and trial

There were more than 20 speakers who addressed the judge, including teachers, students and parents of students from the STEM School community. They each spoke of profound changes in their lives since the events of May 7, 2019.

“This man issued a life sentence to our community. He sentenced Kendrick to death, he sentenced John and Maria (Kendrick Castillo's parents) to a life without their beautiful son,” said Nyki Giasolli, whose daughter was in Room 107. “He sentenced us all to a lifetime of trying to feel joy while simultaneously feeling gut wrenching sorrow for John and Maria.”

Throughout the hearing, Kendrick and the sacrifice he made that day were remembered by many.

“I know I will never be able to repay Kendrick and his parents for what they’ve lost,” wrote STEM School student Nui Silberstein in a letter that was read by her mother. “But I will spend the rest of my life trying to make sure that this family's sacrifice is not forgotten.”

School graduate Alison Thompson said she feared that her memories of Kendrick, who she called her best friend, would someday fade.

“I live every day afraid I might forget what Kendrick’s laugh sounded like,” she said. “I dont think I’m ever going to get to experience happiness again as I did in those moments with Kendrick. I’ve never met someone who could make everyone around him so happy so effortlessly. Now he’s gone.”

Often speaking through heaves and sobs, victims and their loved ones asked the judge to never allow Erickson to see the outside of a prison again.

“Someday I’ll overcome my PTSD and be able to go out in public with my family again,” said Aiden Morrisson, who was an eighth grader at STEM School the day of the shooting, “But I hope Devon can’t. I hope Devon suffers as much pain as he’s put me through. I hope Devon is in prison for the rest of his life and never sees the outside world again.” 

Some speakers directed their comments directly to Erickson, looking him in the eye while they told him the results of his actions.

“You’re a coward and a murderer,” said Kalissa Braga, a parent of students at STEM.

'We're so confused'

Several of Erickson’s family members spoke about what happened that day during the sentencing hearing. They described him as someone completely different than what has been portrayed in the trial.

Instead of a coldblooded killer, they described a loving, talented young man who loves hugging, playing music and spending time with his friends.

Through bursts of emotion, his father Jim Erickson spoke about his son, calling him his best friend.

“We love Devon unconditionally and we're so confused how this could have ever happened," Jim Erickson said. “We hope that someday others can forgive Devon.”

His parents apologized to the victims of the attack, saying they have prayed for them daily since the shooting.

“I hope God is listening,” said Stephanie Erickson, Devon’s mom. “And I hope he can help everyone.”

Erickson's girlfriend, a family friend and his grandfather also spoke in support of him.

"He's a loving, caring, absolutely outstanding person," said Joe Hershferldt, Erickson's grandfather.  "He made a big mistake but he's a great guy."

Under state law, Erickson faced a mandatory sentence of life in prison without chance of parole. At issue Friday was whether extra years would be added to the sentence.

Former District Attorney George Brauchler, who remained with the office to prosecute this case, spoke to the judge about the significance of adding additional years to the mandatory life sentence.

“The number does matter, Judge. It matters to these people right here. It could matter to a future judge, it could matter to a future legislature,” he said. “It matters to this community.”

Judge Slade  spoke directly to Erickson before delivering her sentence,  giving her perspectives on the crimes he committed.

"I haven't seen and I haven't heard that you've accepted responsibilty for this," she said. "No sentence I impose is going to change that. That's on you."

She said she hoped  the sentence she put in place would deter crimes like this from happening  in the future and that she considered his actions "so heinous, so violent and so far reaching" that they warranted the sentence she gave.

Details from trial

During the 12-day trial, which occurred in May and June, the jury heard from 63 witnesses, with only two of them being called by the defense. 

The prosecution called on STEM School students and teachers, doctors, forensic experts, first responders and others to share their insights into what happened that day. 

Erickson’s partner in the deadly attack, McKinney, also testified for the prosecution. McKinney, now 18, told the jury that he and Erickson had an elaborate plan for the attack that included killing everyone in Room 107 of the school. The plan, McKinney said, was for Erickson to kill McKinney so he could “come off as the hero.”

That testimony contradicted earlier statements made by both shooters in the immediate aftermath of the attack. At that time, both said McKinney had forced Erickson to participate.

During cross examinations and direct questioning of two expert witnesses, Erickson’s defense attempted to convince jurors that Erickson had not meant to hurt anyone that day and that instead, he accidentally fired his gun and that he was imparied by long-term cocaine use at the time.

Prosecutors repeatedly rejected this narrative by asking witnesses to confirm that Erickson had been coherent earlier in the day and in the moments before the shooting. They also drew attention to the lack of academic studies that cite accidental trigger pulls for multiple gunshots.

Physical evidence discussed during the trial showed that Erickson had fired four times, hitting three students. McKinney shot nine bullets, injuring four students. Many injured in the attack spoke during the trial, sometimes giving emotional testimonies about the trauma they experienced.

Mitchell Kraus, a senior at STEM School during the attack, told the courtroom how he ran from the school for several blocks before he realized he had been shot. Another student who was shot, Lucas Albertoni, spoke about the moment he looked down the barrel of a gun and pleaded with McKinney to spare his life.

Other testimony came from teachers in the room that day, law enforcement officers who responded to the attacks and friends of the shooters.

Prosecutors also played recordings of several calls Erickson made during his time awaiting trial in jail. In one, he laughed and referred to himself as his girlfriend’s “school shooter boyfriend.”

“I technically shot up a school,” he said in the call.

Erickson was also found guilty of possession of a weapon on school grounds and reckless endangerment.

Erickson’s defense attempted to persuade jurors that McKinney’s testimony was part of a deal he had made with prosecutors to get a reduced sentence. 

Erickson pleaded not guilty in January 2020, and his trial was delayed several times due to the COVID-19 pandemic. 

Jurors deliberated for five hours before they returned the guilty verdicts.