MOORESVILLE, Ind. – Fears of a threat prompted Mooresville Schools to call for an e-learning day on Thursday--and now officials have revealed the reason behind the decision. The school district previously said a “threatening situation” led it to keep students at home on an “asynchronous, non-livestream learning schedule.” The district later released an update in conjunction with the Morgan County Sheriff's Office that revealed a "suspicious item" found on school grounds was left over from a training exercise, leading to concerns about a possible threat. "This morning’s situation involved a suspicious item found on the Mooresville High School campus," the statement said. "After a thorough investigation, it has been determined that the item was part of Wednesday overnight training from the Morgan County Sheriff’s Office. The item was left behind accidentally when officers left for an urgent call." The statement went on to explain that "outside law enforcement training" happens frequently on campus. "We are incredibly thankful to the school custodial staff for their daily campus checks and their immediate alert early this morning," the statement said. "We are also thankful to our Mooresville Schools Police Department for their immediate response. We do not regret taking full measures to keep students and staff safe and will always do so." Mooresville Schools said students would still have an e-learning day. After school practices and activities will proceed as normal. Here’s what the school initially posted on social media: Due to a threatening situation, Mooresville Schools will be on an e-learning day today, Thursday, September 19. All students will be on an asynchronous, non-livestream learning schedule. Students should check Canvas and Google classroom for lessons. School officers and administrators are working actively with local law enforcement to fully assess the situation. Mooresville Schools A series of recent school threats likely intensified Thursday's response. In recent weeks, schools have been inundated with various threats. Across the state, police have made more than 20 arrests related to school threats; those include cases in Marion, Anderson and Indianapolis, among other communities.