— A west suburban elementary school was put on lockdown Monday morning after someone broke a window, then placed a “suspicious” envelope inside an office area.

It happened at 9:56 a.m. at St. Peters Church and School at 1881 Kaneville Rd. in Geneva, a release from Geneva police said.

School personnel told police a suspicious envelope was placed in the office area where a window had been broken.

The envelope contained an unknown substance and the school administration, and Geneva Police and Fire departments, determined the school should be placed on lockdown, the release said.

With the help of firefighters, police learned the substance was a non-threatening household product and as of about 1 p.m., students and personnel were allowed back inside and returned to their school day.

Geneva police are investigating.

Watch & Listen LIVE