Wheaton police said an individual called 911 around 9:30 a.m. stating they were armed with a firearm and explosives and they were walking into the school with the intent to kill everyone.
While school is not in session due to the President's Day holiday, students and staff who are at school were evacuated while police investigated the threat and searched the building.
Wheaton police also asked anyone who is within a two-block radius of the school to shelter in place and stay indoors while police investigated.
As of 10:45 a.m., Wheaton police said the shelter in place order had been lifted. Police later confirmed that they did not find any armed individuals or threats within the building.
Wheaton police said other municipalities had received similar threats within a similar timeframe, so this is being considered a "swatting" incident in which a false threat is called in to draw a large law enforcement response to one location.
Wheaton police said they were have an increased presence outside of Wheaton schools on Tuesday when school is back in session.