Verdict reached in Tri-Cities school shooting plot involving manifesto and maps

A student who plotted a shooting at Kamiakin High School in Kennewick has been found guilty of attempted first-degree murder armed with a gun.

Judge Jacqueline Shea-Brown ruled Friday afternoon in a non-jury trial that Mason Bently-Ray Ashby, now 15, also is guilty of threats to bomb or injure property and 11 counts of second-degree illegal gun possession.

Benton County Prosecutor Eric Eisinger said after the verdict that the reason the Tri-Cities did not have “a terrible shooting” at Kamiakin High came down to two brothers across the country who reported a TikTok post by Ashby and the quick work of the Kennewick Police Department to investigate what appeared to be a plan for a school shooting.

On Sept. 19 a 12-year-old in Florida saw a TikTok video that appeared to show a map for a school shooting.

The boy’s family notified the FBI and within 24 hours, on a Saturday evening, Kennewick police had arrested Ashby, then a 14-year-old ninth-grader at Kamiakin High.

Prosecutors had to prove Ashby was not only planning a mass shooting, but had taken substantial steps to carry it out.

Eisinger said in his opening arguments that Ashby’s plan was not a passing fancy.

He had a morbid fascination with school shootings and looked up to school shooters, he said.

TikTok traced to Kennewick

Eisinger argued that Ashby had a plan, a gun and a videotaped “dress rehearsal” walk through the high school recorded one day before he was arrested.

Kennewick police also found screenshots Ashby made of what the teen called his manifesto, which Eisinger said was key evidence as the trial started.

The teen created three maps found by law enforcement that showed specific plans for a shooting at Kamiakin High. One was featured in his TikTok video, another was found in his bedroom and the third was created by Ashby after he was jailed in the Benton-Franklin Juvenile Detention Center.

Shea-Brown dismissed the defense’s argument that Ashby only fantasized about a school shooting.

The TikTok video he posted under the user name Waffenblud, meaning blood weapon in German, was very specific and color coded, she said. It showed multiple classrooms and the library marked as shooting targets.

Ashby tagged a comment under his short video with a “like,” the judge pointed out. The comment said “planning on shooting up a school or sum (something).”

The internet protocol, or IP, address linked to the TikTok post was traced to the Kennewick home of Ashby’s grandparents, where Ashby lived.

There Kennewick police seized another map that gave a lunch period as a peak time for students and noted “could shoot through windows.” Police also found at the house drawings and notes about mass shootings.

Manifesto key to verdict

The judge read from Ashby’s manifesto to explain her verdict.

“Hey, you found my manifesto,” it starts. ”I’m sure you will all be laughing at me by the time you figure out who I am and why I did what I did, especially you people at WDP (a website with death videos.)”

“I wonder if you’ll find my accounts haha. I’m sure my discord and other social media will be released nearly instantly after the massacre,” he wrote. “I’ve sent close friends photos of me that will be considered rare or unreleased by the time my plan goes through, Hell maybe i’ll even record the attack and send it to a few ....”

The manifesto continued to describe other instances of school shooting and Ashby’s desire to gain access to a gun.

On June 20, he added to the manifesto, describing how he guessed the combination to his grandfather’s gun safe based on smudged numbers on its keypad.

Ashby then made videos and photos of himself with many of the guns, excitedly showing them off and clicking and pointing them, the judge said. Thankfully there were no rounds in the guns, she said.

Kennewick Detective Alexander Holden, whose investigative work Eisinger described as “phenomenal,” also discovered a video on Ashby’s phone taken the last school day before his arrest of the teen walking around the Kamiakin campus

Ashby commented on glass windows he could shoot through and then said, “Gonna be like Parkland,” where 17 people were killed in a mass shooting at a Florida high school in 2018. He also added, “Sandy Hook, and just like ....,” before his voice trailed off. At Sandy Hook Elementary in Connecticut, 26 people were killed in 2012.

Documents he created, evidently from memory, while he was in juvenile detention ranked mass shooters and arranged them as if they were being given awards.

The judge also took note that Ashby had taken a Glock 22 and a magazine from his grandfather’s gun safe to a friend’s house on the day he was arrested.

When his grandmother called him to say the police wanted to talk with him and that he needed to come home, he left the pistol and magazine with the friend.

Not a victimless crime

Ashby appeared impassive Friday as the judge gave her verdict and explained her reasoning, but later wiped his eyes with a tissue.

The maximum juvenile court sentence for attempted murder that Ashby can receive would keep him incarcerated in a juvenile facility until he turns 21. His sentencing hearing has not been scheduled.

Eisinger said Washington state law would not allow a 14-year-old to be charged as an adult for attempted murder. That would only have been possible if a first- or second -degree murder had been committed.

“This was not a victimless crime,” Eisinger said after the verdict. “It really impacted the Kamiakin community and the community as a whole. I’m thankful justice was done.”

This story was originally published January 30, 2026 at 8:55 PM.