Boulder Police Arrest 18-Year-Old in Fatal Halloween Shooting at CU House Party

Key points

• Omar Perez, an 18-year-old from Thornton who is not a CU student, was booked in Boulder County Jail at 9:39 a.m. Monday.
• Perez faces one count of first-degree murder, one count of attempted first-degree murder, and one count of first-degree assault causing serious bodily injury with extreme indifference.
• The shooting occurred around 11:28 p.m. on Oct. 31 at a residence in the 700 block of Marine Street, where two 19-year-old CU students were shot.
• One victim died early Sunday; the other remains in critical condition at Boulder Community Health.
• Police arrested Perez with assistance from Thornton and Westminster police departments and the Adams County Sheriff’s Office.
• Perez is scheduled for a hearing on advisement in Boulder County District Court on Tuesday afternoon.

Background

This incident marks Boulder’s first homicide of 2026, according to Boulder Police Chief Steve Redfearn. The shooting followed a registered Halloween house party that was shut down by police around 10:02 p.m. due to a noise complaint. Earlier coverage noted that hundreds of attendees left after the shutdown, but a smaller group remained. The victims have not been publicly identified by the Boulder County Coroner’s Office. CU Boulder has activated support services, including the Office of Victim Assistance and Counseling and Psychiatric Services, for affected students.

How outlets are covering it

Axios and the Daily Camera report that an arrest affidavit indicates Perez opened fire after a group including him was kicked out of the party, and that he forced his way back inside, sparking a fight. A witness told investigators he put Perez in a headlock to break up the fight, after which Perez fired approximately three shots into the crowd, striking one person in the neck and another in the leg. The City of Boulder initially released photos of two persons of interest, including a man in a red hooded sweatshirt and another in an Art the Clown shirt, but did not name them. Colorado Public Radio reported the shooting without identifying a suspect at the time of its initial release. All sources agree that the shooting occurred after police shut down the party and that a group attempted to force entry into the home. Boulder County District Attorney Michael Dougherty stated that the prosecution team will pursue justice relentlessly. Governor Jared Polis expressed condolences to the victims and the CU Boulder community.

Why it matters

The arrest provides a critical development in a case that has drawn significant public attention due to its proximity to a major university and its timing during a widely attended Halloween event. The case highlights ongoing concerns about safety at large house parties in Boulder and the challenges of enforcing noise ordinances and managing crowd dispersal. The fatal shooting has prompted university and local authorities to activate support services and seek public assistance in identifying other individuals involved. The legal proceedings will test Colorado’s strict bail laws for first-degree murder charges and the city’s response to violent incidents in residential neighborhoods near campus.

What to watch

Perez will appear for a hearing on advisement in Boulder County District Court on Tuesday afternoon. Boulder police continue to seek information from individuals who attended the party or have video footage, asking them to contact dispatch at 303-441-3333 and reference case 26-10148. The Boulder County Coroner’s Office has not yet released the identity of the deceased victim. Additional charges may be filed against other individuals involved, though detectives have stated that Perez was the only shooter. CU Boulder support services remain available 24/7 for students affected by the incident.