COLVILLE, Wash. - A 10-year-old boy who plotted to attack a classmate at a Colville Elementary School has been sentenced to 3 to 5 years in a juvenile detention facility. A Stevens County Superior Court Judge sentenced the boy on Wednesday in Colville. The Stevens County Prosecutor asked for an exceptional sentence that would have put the boy in custody until at least the age of 16. The boy pleaded guilty just before the start of his trial in April. He was charged with conspiracy to commit murder, juvenile in possession of a firearm and witness tampering. The second defendant in the case, an 11-year-old boy, remains in custody. The two fifth-graders were arrested Feb. 7 after officials discovered them trying to sneak a gun and knife into Fort Colville Elementary School.