Police in Washington state last week arrested a 13-year-old boy “with school shooter ideations who was making threats to kill.”

Investigators from the Pierce County Sheriff’s Office discovered 23 firearms and multiple boxes of ammunition during a home search, noting that “firearms were mounted on walls and easily accessible, and handguns were found unsecured throughout the residence.”

The police stated they found evidence in the boy’s bedroom suggesting “he was fascinated with past school shooters and mimicked similar behaviors, evident from photos and inscriptions throughout his room.”

Despite not finding evidence that the teen planned a shooting, detectives said he seemed to have “everything ready for committing a mass shooting incident.”

They discovered loaded magazines with “school shooter writings on them,” as well as clothing and other writings “indicative of a typical mass shooting scenario.”

The boy was last enrolled in school in 2021, they said.

The boy was arrested on September 6 and appeared in court on Monday, where he pleaded not guilty to five charges, including one count of threatening to bomb or damage property and three counts of unlawful firearm possession, KOMO reported. The fifth charge was a misdemeanor.

The boy’s parents told KOMO that the situation was a misunderstanding and that the charges were exaggerated. The teen’s mother claimed his menacing social media posts were merely an attempt to “be cool” among friends, while his father insisted he had no plans of harming anyone.

The investigation began last Friday based on social media posts, police said.

“A lot of the tips that we’ve received came from social media posts with this suspect boasting about his access to firearms and his intentions to kill and create a mass shooting incident,” said sheriff’s office Public Information Officer Carly Cappetto,

“If you could compare what we found in our evidence from this case and compare to past recent major mass shootings that we’ve had in schools, every single box was checked that something bad was going to be happening,” she added.

The teen, who has not been publicly named, remains in custody at the county juvenile detention center pending a review hearing on September 22, KOMO said.

Capetto said that it wasn’t clear how many, if any, of the guns found in the home were obtained illegally. Some had no serial numbers, making them “untraceable,” and some appeared to be 3D printed.