Monroe man arrested for murder of girlfriend’s 2-year-old daughter in Snohomish County

A 27-year-old Monroe man is under arrest, charged with murdering his girlfriend’s 2-year-old daughter and assaulting her 5-year-old son in Snohomish County.

The Pacific Northwest Violent Offender Task Force arrested the suspect Tuesday night at a motel on Old Owen Road. He faces charges of second-degree murder of a child and second-degree assault of a child.

Girl died at Seattle Children’s Hospital

Deputies were originally called on December 1, 2025, to a residence in the 300 block of Avenue J in Snohomish for a report of an unresponsive 2-year-old girl, the Snohomish County Sheriff’s Office (SCSO) stated in a news release Wednesday.

Fire personnel performed CPR at the scene, and the child was transported to Providence Regional Medical Center. She was later transferred to Seattle Children’s Hospital, where she died on December 7, 2025.

Hospital staff alerted the Sheriff’s Office’s Special Investigations Unit.

Findings of the investigation

During the investigation, detectives learned the 2-year-old victim and a 5-year-old child were at home in the sole care of the 27-year-old suspect at the time of the incident.

The suspect told investigators the 2-year-old fell in the bathroom and hit her head, but the Medical Examiner ruled her injuries were inconsistent with a fall. Detectives also discovered the 5-year-old child had injuries to his neck and arm, which they believe were caused by the suspect.

The suspect is not related to either child and was in a dating relationship with the children’s mother at the time.

The Snohomish County Medical Examiner’s Office determined the girl’s cause of death was blunt force head trauma, and the manner of death was homicide.

Why the arrest took time

Renee Cooper, public information officer for SCSO, said the case has been under investigation since December, and that the arrest followed extensive medical and forensic work.

After the medical examiner’s initial investigation, additional testing was required.

“All of those labs have to go to a different kind of lab, like a neurological lab, to do more investigation to make sure that what they think happened is actually what happened, and to do it thoroughly. That way, you know the person stays behind bars,” Cooper explained.

Cooper described the case as “heartbreaking” and “absolutely awful,” and said the sheriff’s office had been waiting for the case to develop to the point where an arrest could be made.

The suspect is due in court Wednesday afternoon.

Contributing: James Lynch, KIRO Newsradio

Frank Lenzi is the News Director for KIRO Newsradio. Read more of his stories here.

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