CASS COUNTY— Authorities are investigating a threat that has closed a south of Kansas City.

The Archie R-V school district said in a Facebook post that the written threat was discovered in a building Wednesday and bus riders would be taken back home.

If an adult is present they’ll be dropped off. But if an adult isn’t home, they will be taken to an off-site location until arrangements can be made to have them safely picked up.

The small Cass County town of Archie is located 45 miles south of Kansas City. The Cass County Sheriff’s Office didn’t immediately return a phone messages.