Officials say the boy had a list that named several students and administrators.
School district Superintendent Dr. James Chapman says they followed their procedures and contacted police.
Investigators said two students collaborated on the list. Police removed them from the school for questioning.
The students insisted the whole thing was a joke, authorities said. It was no joking matter for police. One of them was charged with making terroristic threats.
Investigators did not find any weapons in the school, but they also plan to search the students' homes. Both teens face expulsion hearings, school officials said.
School officials said students were sent home with a letter notifying parents about what happened.
