The Olympian reports (http://is.gd/GMYFDE) that police found three guns and ammunition in the boy's home, and arrested him Monday.
Thurston County Deputy Prosecutor Wayne Graham said Tuesday in court that the boy had expressed a "fascination with Columbine," the 1999 school shooting in which two student gunmen killed 12 students and a teacher before killing themselves.
Tumwater police Detective Jen Kolb says police went to the student's home after hearing of the threats to shoot students at Black Hills High School.
A juvenile court commissioner ordered the boy held pending a mental evaluation. Graham says the teen was arrested for investigation of harassment and unlawful possession of a firearm.
Graham says the guns included a 9 mm pistol, a shotgun and an "assault-style weapon."
The boy's mother told the court her son "had some depression issues."
Information from: The Olympian, http://www.theolympian.com