A mortar shell left at the Douglas County Judicial & Law Enforcement Center turned out to be a training shell that was not explosive, Lt. Doug Woods said.

The U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives removed the item from the south side of the courthouse around 4 p.m. It had been brought there in a styrofoam cooler by a citizen who found it while cleaning out a storage unit.

Woods said an ATF agent determined after looking briefly at the shell that it was a solid metal shell used for training that’s designed to be shot into the air- but not to explode.