Psychiatric evaluation has started for a 15-year-old boy who was arrested earlier this week. Police had reports he had threatened to shoot up the Niangua High School. The boy has been taken to a Greene County facility for a four-day evaluation. In East Prairie, a 16-year-old high school student has been arrested after police traced to his home computer some website messages threatening to kill children at school. And In Charleston, another 16-year-old student has been arrested on suspicion of making a threat to bomb the school.