Court process in Fall City mass shooting has been slow, adversarial

Eighteen months after a teen allegedly killed his parents and three siblings in Fall City, the court has still not determined if he will be tried as an adult.

The process continued on Wednesday with another court hearing, in which defense attorneys had sought, but failed, to close part of the proceedings to the public during a decline hearing - when a judge decides whether the teen will be tried in adult court or have their case adjudicated as a juvenile.

The teen is charged in juvenile court with five counts of first-degree aggravated murder for allegedly killing five members of his family in their Fall City home in October 2024, when he was 15. The Seattle Times typically does not name juvenile suspects unless they are charged as adults.

Those killed in the mass shooting were 43-year-old Mark Humiston, 42-year-old Sarah Humiston, and three of their children: Katheryn Humiston, 7; Joshua Humiston, 9; and Benjamin Humiston, 13. The middle child, a then 11-year-old girl, was shot but escaped through her bedroom window.

The last year has been unusually adversarial and arduous, and marked by a protracted discovery process as attorneys investigate the now 16-year-old and his family's background.

In briefings, the defense has argued that the King County prosecutor's office has made inflammatory and extrajudicial" statements to the press and that attorneys have not had appropriate access to evidence.

Prosecutors have claimed that defense attorneys tampered with and removed evidence from the crime scene (the judge found no misconduct was committed) and that defense attorneys have made misstatements of fact and irrelevant legal arguments.

Ultimately, the case has dragged. Once a decision is made - a decline hearing is currently scheduled for this summer - it could take many more months to go to trial.

A tense courtroom

Appearing in court on Wednesday, the teen appeared noticeably older compared with his first court appearance - his hair was grown out and a touch of stubble lined his face.

The tense atmosphere between prosecution and defense permeated the courtroom, and Judge Veronica Galván appeared, at times, impatient.

Attorneys for the teen asked the decline hearing be closed to the public and media during discussion of mental health evaluations and other aspects of his past, arguing the teen's constitutional right to a fair trial and the statutory interest in maintaining his privacy outweighed the public's right for the courtroom to remain open.

Defense attorney Amy Parker described the motion as a "narrowly tailored, limited closure."

Galván disagreed, finding that granting the motion would essentially result in a full closure to the media and public.

"People have a right to know how their courts function," Galván said while denying the motion without prejudice, meaning defense attorneys could make another attempt at a later date.

Caesar Kalinowski IV, an attorney representing The Seattle Times and KING 5, was also at the hearing to oppose closing the courtroom to media.

While 16- and 17-year-olds charged with murder and certain other serious violent offenses can be automatically charged as adults, a discretionary decline hearing is required before younger teens can be charged in adult court.

In the hearing, the judge must weigh eight Kent factors, including the seriousness of the offense; the sophistication and maturity of the juvenile; the prospects for adequate protection of the public; and the likelihood of rehabilitation.

If the teen's case is adjudicated in juvenile court, he would be released at age 25. If he is convicted in adult court, aggravated first-degree murder carries a sentence of 25 years to life for juveniles.

Potential arguments

In filings, attorneys have hinted at arguments they will make at the decline hearing or at trial.

The teen's attorneys wrote in a briefing that interviews with family and friends indicate the Humiston children "were isolated from the outside world and did not engage socially with many peers."

It appeared the Humiston family had grown "increasingly paranoid of the government and of medical professionals, especially as it relates to the COVID-19 vaccine," in the years before the mass shooting, defense attorneys wrote. The children were home-schooled by their mother, and there are few school and medical records available about the children.

"Initial reports indicate the home was abusive, tightly controlled, and dominated by extreme religious beliefs," the briefing said. "The children were also given access to firearms and raised under a rigid, militant survivalist ideology."

The briefing stated the teen had no criminal history before the shooting and that teachers and family "describe him as kind, respectful, and deeply devoted to his family."

The teen's attorneys have raised the possible argument that the 13-year-old who died during the shooting, Benjamin, was the shooter. During the initial 911 call, the then-15-year-old suspect claimed his brother shot the family.

Defense attorneys noted a sheriff's detective wrote Benjamin "had a recent history of suicidal ideation and had written a letter a few months prior to the incident detailing his recent use of guns."

Prosecutors cited this as a misstatement of evidence. That Benjamin was bullied by other children and commented he wished he was dead is a "far cry" from suicidal ideation, they said.

Detectives and prosecutors allege the teen staged the scene. Benjamin was found with a gunshot wound to the head and with the Glock in his left hand on his chest. The King County medical examiner's office determined that Benjamin was shot in the head from over 2 feet away, and had another wound from a gun that was fired between 6 and 24 inches away, charges say.

The surviving sibling told detectives her 15-year-old brother shot at her, according to charges.

The burden lies with prosecutors to convince the judge that the teen should be tried as an adult. The outcome of the decline hearing has enormous consequences for the teen: punishment as an adult, or rehabilitation as a juvenile. In September, he will turn 17.

"This is the most serious juvenile homicide case we are aware of in King County history and possibly Washington State's history," a defense briefing stated. "This case requires a careful, thoughtful, and methodical approach by everyone involved.

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This story was originally published April 24, 2026 at 11:36 PM.