STEM School Highlands Ranch shooting suspect 18 year old Devon Erickson, facing 48 criminal charges makes a court appearance at the Douglas County Courthouse on May 15, 2019. (Pool photo by Joe Amon/The Denver Post)

CASTLE ROCK — Prosecutors will not pursue the death penalty against a teen charged in a shooting at a suburban Denver school that killed a student.

In a court filing on Thursday, 18th Judicial District Attorney George Brauchler did not explain the decision not to seek capital punishment for Devon Erickson. Brauchler said that the parents of Kendrick Castillo, who was killed in the May 7, 2019, shooting, supported capital punishment.

However, he noted Erickson’s lawyers could have argued against the death penalty because of his age, lack of a criminal history and other mitigating factors. He said it was not appropriate to publicly discuss other factors in his decision at this time.

The decision comes as Colorado is poised to become the 22nd U.S. state to abolish the death penalty. Last week lawmakers approved a repeal bill that Democratic Gov. Jared Polis has pledged to sign. In his filing, Brauchler noted that the bill does not apply to murder cases charged before July 1. 2020.

Erickson, 19, has pleaded not guilty to first-degree murder and other charges in the shooting at STEM School Highlands Ranch. The other student charged in the shooting, Alec McKinney, 16, pleaded guilty last month under a deal that gives him a chance to be paroled after serving 25 years in prison.

Even though McKinney was prosecuted as an adult, he is eligible to be paroled because he was a juvenile at the time of shooting.