Boulder police announced Monday, Nov. 2, that they had arrested an 18-year-old suspect in a Halloween party shooting that killed a University of Colorado Boulder student and wounded another. Omar Perez, of Thornton, was taken into custody earlier Monday on charges of first-degree murder with extreme indifference and attempted first-degree murder with extreme indifference. Officials said Perez is not a CU Boulder student.
Investigators believe Perez was the sole shooter, according to a police news release, although other people involved could face additional charges. The shooting occurred around 11:28 p.m. Saturday at a house near 7th and Marine streets in the University Hill neighborhood. Police said it was Boulder's first homicide of 2026.
Officers had visited the same house earlier that day following a noise complaint. Hundreds of people had gathered there for a Halloween celebration, and police issued several citations before shutting down the party. A smaller number of people stayed inside. Detectives said a group later tried to force its way into the house, followed by a confrontation and gunfire that struck two people. The suspects then fled.
An arrest affidavit obtained by Denver7 on Monday described the confrontation in greater detail. According to the document, Perez and five others had been removed from the house before Perez returned and pushed his way inside. Fighting broke out both inside and outside the home before the shooting.
One witness told investigators that he held Perez in a headlock after Perez allegedly ran toward the witness's friend. The witness reported hearing a pop that initially sounded like a balloon, then seeing a black handgun and an orange muzzle flash as two more shots were fired. He identified the weapon as a Glock 19 and said Perez ran away immediately afterward, according to the affidavit.
Officers found two wounded 19-year-old men, both CU Boulder students, and both were transported to Boulder Community Hospital. One died early Sunday. Police reported Sunday that the surviving student was in critical condition; no more recent condition was available. The Boulder County Coroner's Office will release the deceased student's identity later. Both families have asked for privacy and do not want to speak with reporters.
Police established probable cause to arrest Perez using evidence that included photographs supplied by a witness matching the suspect's description and information from a family location-sharing app. According to the affidavit, the app showed Perez in Boulder for roughly 30 minutes and leaving about two minutes after police received the shooting call.
Investigators interviewed about 20 witnesses and identified two people they want to question. One was described as a man with facial hair and short dark hair who wore a red hoodie beneath a black jacket. The other had short dark hair and wore a black T-shirt featuring Art the Clown. Police released photographs and doorbell footage showing the people leaving the house and returning inside.
Anyone who recognizes those individuals, attended the gathering or has information about the shooting is asked to call Boulder Police dispatch at 303-441-3333. Photos and videos can also be submitted online. Gov. Jared Polis said he was closely following the investigation and urged people with information or images to assist police.
