Boy accused of murdering 5 members of his own family tried to pin massacre on his little brother, police say

The 15-year-old boy arrested in connection with the murder of his two parents and three siblings tried to pin their deaths on his little brother, court records reveal.

Prosecutors charged Andrew Humiston this week with five counts of first-degree murder and one count of attempted murder after his parents and siblings — ages seven, nine and 13 — were found dead 30 minutes outside of Seattle in Fall City, Washington on Monday, according to court documents from the King County Prosecutor’s Office reviewed by The Independent.

“Based on the evidence at the scene, the evidence discovered during autopsy and BAH’s statements, it appears that Andrew Humiston systematically murdered his mother, father, two brothers, and sister, and attempted to murder his other sister,” the Certification for Determination of Probable Cause document reads.

Andrew called 911 the day of the murders and claimed his 13-year-old brother killed his parents and siblings before taking his own life.

“He just shot my whole family and committed suicide too,” he told the 911 operator, according to the court documents.

Andrew also told the operator his brother was caught watching pornography the night before and was scared he was about to get in trouble.

When police arrived, they found his parents Mark and Sarah Humiston dead along with three of his siblings. However, Andrew’s 11-year-old sister had managed to escape by playing dead during the shooting, the court documents revealed.

The 11-year-old, referred to only by her initials BAH in court documents, spoke to a 911 operator after fleeing to a neighbor’s home.

She told the operator she heard gunshots and screaming before Andrew shot her, hitting her in the hand and neck. She then played dead before escaping through a fire window in her room, according to the court documents.

“Later in the call, the dispatcher asked if BAH was sure the shooter was Andrew Humiston, and BAH confirmed it was him,” the court documents state.

Paramedics took the 11-year-old to a local hospital, where she answered more questions for the police, the court documents indicate. She told the officers Andrew had recently gotten in trouble for failing some tests, and that Andrew had used their father’s Glock pistol, which he kept in a lockbox.

She also said Andrew was the only kid in the house who knew the lockbox’s combination.

Community members said Mark and Sarah Humiston “often kept to themselves” and homeschooled their children, local outlet Fox13 reported earlier this week. Mark Humiston worked as an electrical engineer in Seattle, the Associated Press reported.

“I’m shocked,” neighbor Lynne Trowern told Fox13. “I kept bursting into tears. I keep seeing the faces of the children, I don’t know the details or anything, but I know something terrible has happened there.”

This shooting marks the 25th mass murder this year, according to the Gun Violence Archive.

Andrew is now in custody at the Clark Child and Family Justice Center, which is for children, the King County Prosecuting Attorney’s Office said in a news release. Proseuctors are now asking a judge to schedule a hearing to determine whether Andrew will be tried as an adult.

If Andrew is tried as an adult, he could face 25 years to life, the news release said. However, if the case remains in juvenile court, he could only be sentenced to prison until he’s 25 years old with no further sanctions.