NEW CASTLE, Pa.—Police have charged an eighth-grader with compiling a "kill list" of nine students and two teachers on a tablet computer in his western Pennsylvania classroom.

New Castle police aren't identifying the 13-year-old because he's being charged in juvenile court with 11 counts of making terroristic threats.

Officials with the New Castle Area School District referred questions to police Chief Robert Salem who says the incident happened March 8 at the district's junior/senior high school.

Another student saw the list being created and alerted school officials, but the boy deleted the information before authorities confiscated the tablet. Police contacted the manufacturer who helped investigators retrieve the information, which prompted police to charge the boy on Thursday.

Police say the boy is undergoing a mental evaluation. They don't know why he named those on the list.