Prosecutors want to send the case of a Fall City teenager accused of murdering his family to adult court

KING COUNTY, Wash. — That’s what the King County Prosecutor’s Office is trying to do refer the case against a 15-year-old boy accused of murdering his family to an adult court.

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

“This process takes months in 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, spokeswoman for KCPAO.

The hearing to decide whether the case will go 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 teenager shot and killed all six members of his family early Monday morning at their home on Lake Alice Road near Fall City.

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 Sarah Humiston, 42.

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

Charging documents say the 15-year-old suspect went to another neighbor’s house and called 911, claiming that his 13-year-old brother, Benjamin, had murdered the family.

Sheriff’s investigators say a 15-year-old boy staged the crime scene and then tried to blame the shooting on his brother.

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

The 15-year-old is represented by lawyers from the King County Department of Public Defense.

In a statement, defense attorney Amy Parker noted that the only evidence provided by the sheriff’s office and prosecutors is a 3.5-page affidavit of probable cause.

Given the media attention on this case and the seriousness of these allegations, we want the court to know that we have been contacted by many people in the community who know our client and have confirmed his good character. He was described by them as kind and caring. He is a boy who has many friends, has social interests and makes a positive contribution to his community. However, we are not involved in a release at this time. We want the court to know this information because the only information the Court currently has is the probable cause certificate and the charging documents.”

Earlier this week Judge Joe Campagna issued this order prohibiting the media from disclosing the name of the 15-year-old.

Prosecutors say the decision to send the case to adult court will have serious consequences for the potential sentence.

“If convicted of the charges in adult court, the penalty set by the state legislature is 25 years to life in prison, with the assumption of release after 25 years,” McNerthney said. “The State Indeterminate Sentence Review Board makes the decision on release. If the case remains in juvenile court, the 15-year-old will only be able to remain in custody until the age of 25 – less than 10 years – without further sanctions.”

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