Laramie High School was locked down for about 90 minutes for a dispute between the student, a 16-year-old junior, school administration and the police, reports Casper Star Tribune.
Student Grace Smith, was given a $500 citation by Laramie Police for trespassing after refusing to leave the school.
Smith had already served school suspensions for not complying with mask mandate imposed by Albany County.
She has been warned by school officials that she is trespassing every time she is in the building and does not wear a mask.
In a statement, the district said the school was locked down in order to prevent further interruptions to academic learning.