CASTLE ROCK, Colo. (KDVR) — Accused STEM school shooter Devon Erickson is facing additional charges related to a jailhouse fight between him and another inmate, months before his trial began.

According to a probable cause statement, a Douglas County deputy assigned to the jail in Castle Rock heard loud voices in a dayroom on March 29 just before 5 p.m.

Erickson had squared off with fellow inmate Jordan Benavidez, took a swing and missed, according to the deputy.

When the deputy started yelling to break it up, Benavidez punched Erickson on the left side of his cheek. The deputy ordered the pod to lockdown, placed Benavidez in handcuffs, and directed Erickson back to his cell, which he complied.

During an interview, Erickson told officers Benavidez continued to call him a “murderer” and when Erickson approached, Benavidez took a “fighting stance.”

Erickson was charged with attempted 3rd-degree assault, and Benavidez was charged with harassment for repeatedly calling Erickson a murderer.