Tanner principal Billy Owens said a school resource officer with the Limestone County Sheriff's Department took a 17-year-old boy into custody Tuesday morning.
Sheriff Mike Blakely didn't elaborate on the specific type of threat the boy allegedly made.
"He wrote threats down against teachers and students in a notebook," Blakely said. "A fellow student told the school resource officer, who searched his book bag. He's charged with making terrorist threats and with possession of marijuana."
Blakely said authorities took the boy to a juvenile detention facility in Tuscumbia.
Making terrorist threats is a Class C felony. If convicted, the boy could face a 10-year prison term and a $5,000 fine.