Authorities say the girl’s injuries did not match claims that she choked on rice and fell from playground equipment.

FAIRVIEW, Ore. — An Oregon man has pleaded not guilty to murder and assault charges after investigators said medical evidence contradicted his explanations for the death of his girlfriend’s 2-year-old daughter, who was found unconscious at a public park in March 2025.

Dison Ruda, 28, was arrested June 10 after an investigation that lasted more than a year. The Multnomah County Sheriff’s Office said he was booked on charges of second-degree murder, first-degree assault, third-degree assault and two counts of first-degree criminal mistreatment. Prosecutors allege the child suffered fatal blunt-force head trauma while in Ruda’s care. Ruda first said the girl had choked on rice, according to court documents. He later described a fall from a playground slide. A medical examiner concluded that the child’s injuries were abusive in nature and ruled the death a homicide, authorities said.

The case began at 11:47 a.m. on March 28, 2025, when sheriff’s deputies were sent to Blue Lake Park in Fairview, east of Portland. A park nature superintendent reported seeing Ruda carrying a child who was unconscious, not breathing and apparently unresponsive. According to a probable cause affidavit described by news organizations that reviewed it, the superintendent saw Ruda blowing into the child’s mouth as he walked. She tried to get him to place the girl on the ground so cardiopulmonary resuscitation could be performed properly. Ruda walked toward a blue Honda Odyssey before putting the child on the grass, the document said.

The superintendent began emergency care after the girl was placed down. Ruda told her that the child had choked on rice, according to the affidavit. The superintendent swept the girl’s mouth and performed the Heimlich maneuver but found no food or other obstruction. A younger child was strapped into a car seat inside the nearby vehicle, the superintendent told investigators. Deputies and paramedics arrived as the effort to revive the 2-year-old continued. The first deputy at the scene described Ruda as calm and unconcerned, an observation included in the court account but not itself proof of what caused the child’s injuries.

First responders also saw extensive bruising that immediately raised questions about the choking explanation, according to the affidavit. Bruises were visible on the girl’s chest, neck and jaw. Authorities said some marks appeared inflamed and became more noticeable over time. Police and medical personnel did not believe the injuries were consistent with a child choking on food or with the lifesaving measures performed at the park. An examination later documented additional bruising on the girl’s chin, abdomen and limbs. The reports did not identify any airway blockage that would support Ruda’s initial account.

The girl was taken to Randall Children’s Hospital in Portland. Her initial assessment described bruising across much of her body and raised concern about nonaccidental trauma or possible strangulation, according to the affidavit. A CT scan showed a subdural hematoma on the left side of her brain, a shift in the brain’s center line and widespread swelling. Hospital staff reported that blood was no longer flowing to the brain and that the child’s brain and other organs had been deprived of oxygen. Doctors did not expect her to survive. She was declared dead less than 12 hours after reaching the hospital.

When the girl’s mother saw her at the hospital, she told police, “I think he hurt my daughter,” according to the court documents. The mother said the family had been living at the Bybee Lakes Hope Center and that she had recently started a job with an engineering and logistics company. She told investigators that Ruda drove her to work on the morning of March 28 and then cared for her children. She said the children did not have injuries when she left them. Surveillance video from outside the center supported her description of the morning’s movements, KATU reported from the documents.

Investigators said Ruda later offered a different explanation for the girl’s condition. Speaking through a Chuukese interpreter, he said he had seen the child climb the steps of a playground slide on all fours and fall forward from a height of about 6 feet. He said she landed on her forehead in wood chips and did not wake up. That account shifted the claimed cause of the emergency from an obstruction in the child’s throat to a fall involving the park equipment. Detectives then examined whether the playground surface and the reported fall could explain the injuries found by doctors.

A sheriff’s detective recorded himself bouncing on the shock-absorbing wood chips near the slide, according to the court documents. The medical examiner considered research involving short falls by children, the energy-absorbing ground cover and the pattern of injuries across the girl’s body. The examiner also noted that the child did not have the abrasions expected from falling face-first into wood chips. The injuries involved areas not commonly hurt in innocent falls, the affidavit said. The examiner concluded that the brain injury was caused by abuse rather than the type of playground fall Ruda described.

The Oregon State Medical Examiner’s Office identified the cause of death as an acute left subdural hematoma caused by blunt-force head trauma. The manner of death was determined to be homicide on March 16, 2026, nearly a year after the girl died. A homicide classification means a death resulted from another person’s actions; it does not by itself establish who is criminally responsible. Detectives with the sheriff’s office and the East County Major Crimes Team continued working with prosecutors, medical specialists, the Oregon State Police Crime Lab and child-abuse experts before seeking an arrest warrant.

Deputies and members of the U.S. Marshals Pacific Northwest Violent Offender Task Force found Ruda at about 6 a.m. June 10 near Southeast 92nd Avenue and Southeast Powell Boulevard in Portland, the sheriff’s office said. Sheriff Nicole Morrisey O’Donnell called the arrest the result of months of investigative work and credited detectives, prosecutors, marshals, laboratory personnel and clinical staff who assisted. The sheriff’s office said the scale of the case required specialized training and significant resources. Authorities initially withheld the child’s name to give her family privacy while the court process began.

Ruda has pleaded not guilty. The charges accuse him of causing the child’s death and of assaulting or failing to protect children, but the allegations have not been proven at trial. Publicly available reports did not identify a defense explanation for the medical findings or say whether Ruda’s attorney had challenged the account contained in the probable cause affidavit. The prosecution will have to prove the charges beyond a reasonable doubt, and the defense may contest the state’s evidence, its interpretation of the injuries or the timeline presented by investigators.

The girl’s death is now the subject of an active criminal case in Multnomah County. Future court proceedings are expected to address the admissibility of medical evidence, Ruda’s statements to investigators and the circumstances at the park. No trial result had been reported as of Wednesday, and Ruda remains presumed innocent unless he is convicted.

Author note: Last updated July 15, 2026.