Students were seen returning to buildings after a northwest suburban high school was evacuated and streets were closed in the area for police to investigate a potential threat, officials said Wednesday morning. The Bartlett Police Department said it was responding to Bartlett High School just after 11 a.m. to investigate "a threat" and evacuated the school out of an abundance of caution. Police urged residents to avoid Petersdorf Road and Schick Road "for the time being." No additional details were immediately provided on what the threat entailed. #bartlett #illinois #suburbs #chicagosuburbs #threat #school #highschool