The deranged 15-year-old accused of killing his entire family in their luxurious lakeside mansion in Washington was brought up in extreme isolation and raised under a "rigid", militant survivalist ideology," according to his attorney.
Mark and Sarah Humiston pushed their son toward committing the horrific crime after hammering him and his siblings to years of religious extremism and government paranoia, court documents filed last week show. Prosecutors allege that the couple's eldest son — whose name hasn't been revealed—shot dead his parents, 13-year-old brother Benjamin, 9-year-old brother Joshua, and 7-year-old sister Katheryn during the night last October. His 11-year-old sister managed to survive the massacre by pretending to be dead.
Abusive Childhood Triggered Murders
"A common theme that has been expressed amongst extended family, neighbors, and those who knew the Humistons is that the children were isolated from the outside world and did not engage socially with many peers – only a select few families that went to their church and were friends of their family," the court documents, obtained by KOMO News, said.
"Furthermore, initial reports indicate the home was abusive, tightly controlled, and dominated by extreme religious beliefs."
The accused teen and his dead siblings were homeschooled and raised under a strict, militaristic survivalist belief system, according to the documents.
The Humistons were reportedly extremely distrustful of the government and healthcare workers, particularly in relation to the Covid-19 vaccine, which the defense described as contributing to a life of deep isolation.
The entire family was reportedly given access to firearms, including the handgun owned by Mark Humiston, which the teen allegedly used in his attempt to kill his entire family.
These details emerged from nearly 100 interviews with relatives and witnesses, many of whom described the teen as "kind, respectful, and deeply devoted to his family."
Sympathy with the Killer
Even his maternal grandmother supported him, telling lawyers that Sarah Humiston was "was abusive and demeaning to the children." The woman reportedly told police she had previously warned the Humiston parents that she would report them if the alleged abuse continued.
That alleged mistreatment appeared to reach a breaking point last October when the 15-year-old systematically shot his family members one by one inside their $2 million home in suburban Seattle.
The teen began firing around 5 a.m., coldly shooting each victim and then checking their pulses afterward.
His 11-year-old sister was the sole survivor. She pretended to be dead after being shot in the neck and hand, then escaped through a window to a neighbor's home before he could finish her off, according to police.
Meanwhile, the teen called 911 and falsely claimed that his 13-year-old brother had murdered their family and taken his own life after getting in trouble for viewing pornography the night before.
The teen then staged the gruesome crime scene before emergency responders arrived, trying to frame his dead brother for the murders by placing a gun in his hand, according to the charging documents.
He was immediately arrested at the scene and is now facing five counts of first-degree aggravated murder and one count of first-degree attempted murder.
