Wealthy lakefront neighborhood rocked after family butchered in their own home

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Washington state teen accused of murdering family at lake house

A 15-year-old is accused of killing both of his parents and three of his siblings in their home on Lake Alice in Fall City, Washington, on Monday. His 11-year-old sister survived the attack.

A 15-year-old Washington state boy, charged with murdering his parents and three of his siblings, allegedly tried to stage the scene as a murder-suicide carried out by his younger brother.

The suspect’s 11-year-old sister survived Monday’s attack by playing dead and told police what actually happened, according to court records, The Associated Press reported. New details were made public Thursday about the massacre at the Humiston family’s home on Lake Alice in Fall City, east of Seattle. 

The girl told police that her 15-year-old brother used their father’s handgun and that her brother was the only one of her siblings who knew the code to the lock box where their dad’s gun was kept.

Her brother had recently gotten into trouble for failing tests at school, she told police.

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Mark Humiston, 43, and Sarah Humiston, 42, were identified by a mentor of one of their children. (Facebook/Mark Humiston)

The King County Medical Examiner’s Office identified the victims as Mark Humiston, 43; Sarah Humiston, 42; and their children, Benjamin, 13; Joshua, 9; and Katheryn, 7, The Associated Press reported. Authorities have not released the suspect’s name.

The suspect called 911 around 5 a.m. Monday to report that his 13-year-old brother had slaughtered their family after getting in trouble for looking at pornography, according to an affidavit of probable cause, The Associated Press reported.

A neighbor then called 911 after the surviving girl escaped and shared what happened. Police learned that a neighbor with medical experience had been providing aid to the injured girl, who was shot twice, escaped and ran to neighbors for help.

She was taken to Harborview Medical Center, and she was released from the hospital on Tuesday night, a hospital spokesperson told The Seattle Times. 

When deputies arrived at the home Monday, they discovered a “chaotic scene,” but they immediately took one male teen into custody, King County Sheriff’s Deputy Mike Mellis said in a media briefing.

When deputies entered the home, they discovered five deceased individuals: the bodies of two adults and three children. Once the bodies were discovered, deputies understood that this was a “significant crime scene,” Mellis said.

WATCH: Drone footage shows lake where teen allegedly murdered family

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The suspect was charged Thursday with five counts of first-degree aggravated murder and one count of first-degree attempted murder with a firearm enhancement, all of which have a domestic violence designation, the King County Prosecuting Attorney’s Office said. He is being held in secure detention at the Clark Child and Family Justice Center. 

The case was initially filed in juvenile court based on the suspect’s age, but prosecutors said they are asking a judge for a hearing to determine if the case will be moved to adult court.

The suspect’s attorneys said in court that he has no criminal history, according to The Associated Press.

The judge also ordered the teen to have no contact with his surviving sister.

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A teen was taken into custody and a girl was hospitalized with gunshot wounds. Deputies found three other juveniles and two adults dead at the scene. (FOX13 Seattle KCPQ)

“I only saw the children in the driveway yesterday afternoon,” neighbor Lynne Trowern told Fox 13. “I’m shocked. I kept bursting into tears.”

Neighbors told the outlet that the five kids could be seen swimming, fishing and boating from the water’s edge off the beach of their lakeside home all summer.

“So polite. Homeschooled. It’s unfathomable what’s happened,” a former neighbor said.

“Dad worked so hard and mom was the most dedicated, loyal mother you could ask for,” Rhea Robertson, a soccer coach who mentored one of the victims, told KOMO News. “You thought they were perfect. From the outside, they looked perfect to me.”

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The shooting happened in the Lake Alice neighborhood of Fall City, Washington, early Monday. (FOX13 Seattle KCPQ)

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“It does appear to be a family incident, a domestic violence incident that involves a young man who’s in significant trouble, and involves firearms,” Mellis said.

Mollie Markowitz is a reporter for Fox News Digital. Email tips to mollie.markowitz@fox.com. She joined Fox in 2019 and made her way from producing live news coverage to true-crime documentaries at Fox Nation. She has interviewed Ted Bundy survivors, the children of notorious serial killers, survivor Lisa McVey, members of law enforcement and families impacted by traumatic crime.Currently, she covers national crime stories for Fox News Digital. You can follow Mollie on LinkedIn.