Boulder arrests suspect in Halloween party killing

Omar Perez, 18, was arrested Monday for the fatal shooting of a University of Colorado Boulder student at a Halloween party in the University Hill neighborhood. Boulder Police Department spokespersons confirmed the arrest in a Monday release. Perez, a resident of Thornton, faces charges of first-degree murder for extreme indifference and attempted first-degree murder for extreme indifference. He is not enrolled at CU Boulder, officials noted.

The incident occurred at approximately 11:28 p.m. Saturday at a home near 7th and Marine streets. Police had previously responded to the location for a noise complaint. By that evening, hundreds of people had gathered at the house. Officers cited several attendees before shutting down the event. A smaller group remained inside when the shooting began.

According to the police statement, a group of individuals tried to force entry into the house. Shots were fired during the ensuing scuffle, striking two victims. The suspects then fled the scene. Detectives believe Perez was the only person who fired a weapon, though additional charges against other participants remain possible.

Two 19-year-old men, both CU students, were found with gunshot wounds. Both were transported to a hospital. One died of his injuries early Sunday. The second victim was listed in critical condition in a Sunday update. The Boulder County Coroner’s Office will identify the deceased at a later date. The families of both victims have requested privacy and declined to speak to media.

Investigators interviewed approximately 20 witnesses during the probe. Police identified two persons of interest for questioning. One is a man with short dark hair and facial hair who wore a red hoodie under a black jacket. The second person has short dark hair and was wearing a black t-shirt featuring a design of the character Art the Clown. Doorbell video showed the individuals leaving and re-entering the home.

Boulder Police are asking the public to call dispatch at 303-441-3333 with information. Residents who attended the party or recognize the individuals of interest are urged to submit photos and videos online. This incident marks the first homicide in Boulder for 2026.