Teen Accused in Family Massacre Allegedly Tried to Frame Slain Brother. His Sister Survived to Tell the Story

Authorities have charged a 15-year-old Washington State boy with several counts of murder after five members of his family were fatally shot in their home. 

Mark Humiston, 43, and Sarah Humiston, 42, were fatally shot in their Fall City, Wash., home on Monday, Oct. 21, morning along with three of their children, according to the King County Sheriff's Office. The family's 11-year-old daughter survived the shooting.

The couple’s teenage son, whose name has not been released because of his age, has been charged with five counts of aggravated murder and one count of attempted murder, The Associated Press, KIRO News and KOUW reported, citing King County court records and the King County Prosecuting Attorney’s Office. 

King County Sheriff’s Office deputies responded to reports of a possible suicide around 5 a.m. at the residence, the sheriff’s office previously told PEOPLE.

Responding officers found several victims before soon arresting a juvenile at the scene, per police. 

Now, authorities allege the teenager tried to frame his 13-year-old slain brother for the killings, and told police the child killed himself after shooting the other members, per charging documents and unspecified court records cited by The Seattle Times, KUOW and KIRO News. 

The 15-year-old further called 911 to report the killings, blaming his brother and further claiming that he was holed up in a bathroom hiding from the 13-year-old, police allege in charging documents, per KIRO News and The Seattle Times. 

His surviving sister, identified by The Seattle Times, KIRO News and KOUW as an 11-year-old, reportedly gave a different account to law enforcement. She allegedly told them the 15-year-old, her oldest sibling, allegedly shot at her, per the charging documents.

She said she was on her bunk bed when he allegedly shot her, KUOW reported, citing charging documents.  

The girl managed to escape to a neighbor’s house with wounds to her neck and hand and called 911, per court documents, The Seattle Times reported.

Accounts from the community suggest the Humiston family was well-liked; Mark was a software engineer, per his Linkedin, and Sarah was a former nurse whose license had expired, Washington State Department of Health records show.

Mark's employer told KING 5 in a statement that he was a "respected colleague, mentor, and friend."

One of the children’s coaches, Rhea Robertson, told KOMO News the family appeared “perfect” to her.

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The teenager has been barred by the court from having any contact with his surviving sibling, KUOW reported.

The suspect is scheduled to appear for his arraignment on Friday afternoon. PEOPLE was not able to reach his defense attorney. His public defender claims he has no prior history of violence, per KUOW.