A 15-year-old boy has been charged with a false report of terrorism after telling his mother that people were firing guns at Grand Blanc High School.

There were no shooters or emergency on Dec. 19. But the boy's mother called 911 after getting his text message. Police rushed to the school, just south of Flint.

The school was locked down, and some teachers and students hid in closets. The incident occurred five days after 20 children were killed at a school in Newtown, Conn.

The boy is being prosecuted as a juvenile.  Genesee County Prosecutor David Leyton says the prank was "no joke" for police, teachers and students. He says he'll leave the appropriate punishment up to a judge.

"I think Sandy Hook and all other similar tragedies have resulted in an increased sensitivity not only here in Genesee County but across America," Leyton said. "As a result, in this day and age, we cannot condone, in any manner, false reports of school shootings or other acts of terrorism."

"We take any report of an active shooter in a school building very seriously," said Grand Blanc City Police Chief Steve Solomon. "Our students and the entire community must realize that making a false report of a shooting or a bomb threat or anything similar is a serious matter and will be treated as such by law enforcement." 

The boy will appear in court on Feb. 21.

Copyright 2013 WNEM (Meredith Corporation).  All rights reserved. The Associated Press contributed to this report.