A 15-year-old has been arrested after authorities say his made-up report of a gunman in a classroom led to a lockdown at his high school in New York's Hudson Valley.

The incident happened Monday morning at Arlington High School in LaGrangeville.

Arlington School District Superintendent Brendan Lyons said in a statement a student texted a relative around 10:15 a.m. that there was a "shooter" in the student's classroom.

The relative notified authorities.

Dutchess County Sheriff's Office Lt. Shawn Castano says the threat was "determined to be a prank."

Normal school activities resumed after about an hour.

The student was arrested on a false-reporting charge.

His name wasn't released, as the case is being handled in family court.