Murder in the old Schoolhouse?

Our reporter "Banshkeed" and a 9th grader found a shinbone within the original schoolhouse. The bone was located within a few of the southern entrance to the building. It was a reddish brown in color. The bone was humanoid in shape and seemed to within a few days old. There was also a tray of food on top of a table filled with green food that couldn't be identifed at the time. If the doors are usually locked and very few staff members have access to the monument, who could have left it? And most importantly, where did it come from? Pictures soon to be posted.