Officials at a St. Charles County middle school say they're making some changes to security after a convicted sex offender got into the school building. 

Donald Tate Jr. was arrested August 23rd after getting through a door at the Hardin Middle School.   The door had not closed and locked properly.  Hardin principal Ed Gettemeier says from now on, workers will have to enter the building through the main office. Gettemeier says Tate was confronted by a staff member who went to the school resource officer.   Upon further investigation, police were contacted and Tate was arrested without incident.