Washington teen accused of killing his family, surviving sister explains how she escaped

Washington prosecutors a 15-year-old charged boy at the murder of his parents and three siblings in a house in an affluent neighborhood outside Seattle.

The suspect faces five counts of first-degree murder and one count of attempted murder in connection with Monday’s rampage in the unincorporated community of Fall City, the King County Prosecutor’s Office said.

His parents, Mark and Sarah Humiston, as well as three of his siblings – aged 7, 9 and 13 – were found dead at the scene when emergency services arrived.

An 11-year-old girl, one of the suspect’s two younger sisters, was injured in the shooting and has since been released from a Seattle-area hospital. She managed to escape by playing dead before running to a neighbor’s house for help, according to an arrest affidavit filed in Washington Superior Court for King County.

The suspected shooter was arrested at the scene and has since been held in a juvenile detention facility. During a court hearing on Tuesday, he waived his right to appear and a judge found probable cause to hold him on five counts of murder and one count of attempted murder. Law enforcement officials and his attorneys said he has no criminal history.

The prosecutor’s office said it will request that the case be moved from juvenile court to adult court. If convicted in juvenile court, the teen could only be held until age 25, prosecutors said. If convicted in adult court, he could be sentenced to 25 years to life in prison, with a statutory presumption of release after 25 years.

Molly Campera and Amy Parker, the attorneys representing the suspect, did not immediately respond to a request for comment on the charges, which were filed Thursday. After the initial hearing in juvenile court, they released a statement reiterating that their client has no criminal history. They described him as a teenager who enjoys mountain biking and fishing.

“The law says that our client is presumed innocent of these charges, and we are grateful for a judicial process that requires proof and evidence before a verdict is reached,” the statement said.

Teen shot parents, siblings and tried to frame brother, documents show

The first call to report the shooting was from the suspect himself, according to an arrest affidavit. Just before 5 a.m., the teen called 911 and told dispatchers that the 13-year-old brother had “just shot my entire family and committed suicide,” it said.

Investigators said that based on the evidence, the suspect shot his parents and siblings and then tampered with the scene so he could shift the blame to his brother.

“It appears that (the suspect) systematically murdered his mother, father, two brothers and sister, and attempted to murder his other sister,” an arrest affidavit said. He “then staged the scene prior to the arrival of first responders to give the impression that (his brother) had committed the murders and then committed suicide.”

In an interview with investigators, the 11-year-old girl said she woke up to the sound of a gunshot and saw one of her brothers and her father lying in the hallway, the affidavit said. She told police she witnessed the suspect shoot her sister.

The suspect then entered her bedroom and shot her at least once, the affidavit said. She closed her eyes and held her breath for a while until the suspect left the room. She managed to escape the house through her bedroom window and run to a neighbor’s house, who called 911.

The 11-year-old said she recognized the gun “as her father’s silver Glock pistol,” according to the affidavit. She told police her father kept the gun in a small safe, occasionally near the front door, so he could take it to work. She added that of all four children, the suspect was “the only one who knew the combination” to the key box.

A black Glock handgun was found at the scene, according to the affidavit.

When investigators asked her what problems the suspect was having at home, she told them “he had recently gotten into ‘a lot of trouble’ because he failed some tests at school.”

Father was an engineer, mother was a nurse

Mark Humiston was an electrical engineer for Seattle-based consulting firm Hargis Engineers, where he had a reputation as a mentor who brought leadership and vision to the company, Chris Sheldon, a company spokesman, said in an email to USA TODAY.

“We are blindsided and saddened by the tragic events that led to the loss of a respected colleague, mentor and friend, as well as the loss of immediate family members,” a company statement said.

Sarah Humiston was licensed as a registered nurse, according to the permit The Washington State Department of Health website. Public records show her license expired in 2022.

Mourners gathered Tuesday evening at Fall City United Methodist Church to mourn the Humistons and their children. Local residents who knew the couple and their children said they were a seemingly happy family well known in the community.

“They were very strong Christians. They loved God. You could tell,” said neighbor Camille Sharp told KOMO News. “It’s one of those cliché things like everyone says on the news, ‘You’d never suspect this,’ and it’s true.”

This story has been updated with new information

Contributions: Eric Lagatta and Jonathan Limehouse

This article originally appeared on USA TODAY: Shooting in Washington: Teen accused of killing parents and three siblings