UPDATE: Suspect in 2023 Homicide Arrested in Montana

The suspect in the fatal stabbing of Tiara Atencio in October 2023 has been arrested in Montana.

On Monday, October 13, 2025, the Montana Regional Violent Crimes Task Force, in collaboration with personnel from the Missoula Police Department, arrested 21-year-old Connor J. O'Brien in Missoula, MT. O'Brien is awaiting extradition and currently lodged in the Missoula County Jail on the following charges: Murder in the Second Degree and Unlawful Use of a Weapon.

The victim's family has been notified of the arrest.

Anyone with information about this case, who has not talked with police, is asked to contact [email protected] or 503-823-0479 and reference case number 23-274506.

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***Original Messages Below***

Detectives are seeking the public's help in identifying a person of interest related to the Tiara Atencio homicide that occurred on October 19, 2023. While Trimet provided the Portland Police Bureau with the attached photos of the person of interest, it is important to note the homicide itself did not occur on a Trimet bus.

Anyone with information about this case, who has not talked with police, is asked to contact [email protected]… or 503-823-0479 and reference case number 23-274506.

No further information will be released at this time.

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***Original Messages Below***

The woman who was assaulted in the South Tabor Neighborhood Thursday died from her injuries at the hospital, and the suspect who stabbed her is being sought.

The victim is identified as Tiara Atencio, 22, of Portland. Her family has been notified of her death and provided the attached photograph for public release. A family member is willing to speak to local news media. Media should contact the Portland Police Public Information Officer for contact information.

The medical examiner determined the cause of Tiara's death was stab wounds and the manner of death was homicide. No arrests have been made and no suspect information is being released at this stage in the investigation.

This remains an active investigation by the Portland Police Homicide Unit. Anyone with information about this case, who has not talked with police, is asked to contact [email protected]… or 503-823-0479 and reference case number 23-274506.

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***Original Message Below***

A woman was assaulted in the South Tabor Neighborhood.

On Thursday, October 19, 2023 at 11:05p.m., East Precinct officers responded to a report of an assault in the 6800 block of Southeast Powell Boulevard. Officers arrived and located a victim with serious injuries. EMS arrived and transported the victim to the hospital by ambulance.

The suspect or suspects left the area before police were notified and no immediate arrests were made. No suspect information is being released at this time.

Portland Police Detectives are responding to the scene to investigate. During the investigation, Southeast Powell Boulevard is closed between Southeast 68th Avenue and Southeast 70th Avenue. It will likely remain closed for several hours into the morning commute time.

Anyone with information about this case, who has not talked with police, is asked to contact [email protected]… or 503-823-0479 and reference case number 23-274506.

The PIO is not responding to the scene. Additional information will be released when appropriate.

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