A reported shooting outside a Wisconsin middle school sparked a “mass casualty” warning on social media early Wednesday afternoon. Video posted to X appeared to show a heavy police presence outside Mount Horeb Middle School, roughly 20 miles west of Madison. The Mount Horeb Area School District posted notice that an active shooter visited the school Wednesday, but “did not breach” the building’s entryway. Dane County Police warned citizens to stay indoors as they investigated reports of a shooter armed with a rifle. School district officials implied in an update the situation may have been remedied but did not share exact details. “An initial search of the middle school has not yielded additional suspects,” educators posted on Facebook. “As importantly, we have no reports of individuals being harmed, with the exception of the alleged assailant.” School officials said the threat had been “neutralized” outside the middle school, according to the Milwaukee Journal Sentinel. This is a developing story.