Prosecutors want to move the Fall City teen charged with murdering his family to adult court

KING COUNTY, Wash. – King County prosecutors want to move the case against a 15-year-old boy charged with murdering his family to adult court.

The teen appeared in juvenile court Friday afternoon and prosecutors formally requested the case be moved to the adult court system, but a judge will ultimately decide whether that happens.

“This process takes months for all types of cases – the judge will have multiple opportunities to hear from prosecutors and the defense before making a final decision,” said Casey McNerthney, a spokesman for KCPAO.

A hearing to decide whether the case goes to adult court is scheduled for June 4, 2025.

On Thursday, the teenager was charged with five counts of aggravated first-degree murder and one count of attempted murder.

Charging documents say the teen shot and killed all six of his family members in their home on Lake Alice Road near Fall City in the early hours of Monday.

The King County Medical Examiner's Office identified the shooting victims as Katheryn Humiston, 7, Joshua Humiston, 9, Benjamin Humiston, 13, and parents Mark Humiston, 43, and 42-year-old Sarah Humiston.

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An 11-year-old girl survived the shooting and ran to a neighbor's house for help after escaping out a window. According to a police report, the 11-year-old told police that her 15-year-old brother killed the family.

The 15-year-old suspect went to another neighbor's house and called 911, claiming his 13-year-old brother Benjamin had killed the family, according to charging documents.

Sheriff's investigators allege the 15-year-old staged the crime scene and then tried to blame the shooting on his brother.

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According to a sheriff's office report, the 15-year-old boy was the only child in the family who knew the combination to a locker for a Glock pistol that was kept in the family home.

Attorneys with the King County Department of Public Defense are representing the 15-year-old.

In a statement, defense attorney Amy Parker pointed out that the only evidence she presented from the sheriff's office and prosecutors was a 3.5-page probable cause statement.

Given the media interest in this case and the seriousness of these allegations, we want the court to know that we have been contacted by several people in the community who know our client and have attested to his good character. They described him as friendly and caring. This is a boy who has many friends, has pro-social interests and has made a positive contribution to his community. However, we are not currently working on publishing it. We want the court to have this information because the only information the court has at this time is the certificate of probable cause and charging documents.”

Earlier this week, Judge Joe Campagna issued an order prohibiting the media from revealing the 15-year-old's name.

The decision on whether to move the case to adult court will have a significant impact on the possible sentence, prosecutors said.

“If convicted of the charge in adult court, the penalty established by the state legislature is 25 years to life with a presumption of release after 25 years,” McNerthney said. “The state’s Indeterminate Sentence Review Board will make the release decision. If it remains in the juvenile court, the 15-year-old could only be held until the age of 25 – i.e. in less than ten years – without further sanctions.

The teen will remain in secure custody at the King County Children and Family Justice Center.