Teen sentenced for planned Kamiakin High School shooting in Kennewick
By Dan Thesman on Wednesday, June 24th, 2026 in Columbia Basin News More Top Stories
KENNEWICK — A teenager who planned a school shooting at Kamiakin High School was sentenced Monday to the maximum possible confinement allowed under juvenile law, prosecutors announced.
Benton County Superior Court Judge Jacqueline Shea-Brown sentenced Mason Ashby to 316 weeks — just over six years — of total confinement, ensuring he will remain in custody until he reaches age 21.
Ashby was arrested in September 2025 on the same day law enforcement discovered his plot. The case went to trial in January 2026, where a judge found him guilty of attempted first-degree murder, threats to bomb or injure property, and 11 counts of unlawful possession of a firearm. The sentencing followed a multi-month delay granted to defense attorneys to conduct a forensic psychological evaluation.
During the disposition hearing, numerous Kennewick School District officials and Kamiakin teachers described the profound impact of Ashby’s actions on the community. Judge Shea-Brown ruled that the standard sentencing range was insufficient, imposing an exceptional upward sentence based on a finding of manifest injustice.
Authorities revealed that a catastrophic disaster was averted because two young men in Florida spotted Ashby’s plan on TikTok and reported it to police.
Benton County Prosecutor Eric Eisinger, who personally prosecuted the case, credited the tipsters and the swift, joint investigative work of the Kennewick Police Department and the FBI for their miraculous intervention.
Photo of Kamiakin High School campus courtesy Kennewick School District
