Greendale High School was put on lockdown today after a suspicous person was seen in the building. 

The school was immediately put on “hold” at around 12:30 p.m. for security reasons and students were kept in classrooms while police and school personnel searched the building, according to a release from Greendale Police. 

The students were released from the classrooms after the building was checked and later determined that there was never any threat to the students.

Greendale Police said it's an active investigation and did not say who the suspicious person was.

School district administrators throughout southeastern Wisconsin — and the country — are addressing rumors of shooting threat at their districts.

Districts where threat rumors have circulated include Waukesha, Oak Creek, Menomonee Falls, Hamilton, Arrowhead, Greenfield and Cudahy.