Police said Charles Johnston, 63, reportedly a retired Muscogee County school teacher, for years held a grudge against a Doctors Hospital nurse who had treated his mother before she died at the hospital in 2004. Shortly after 2 p.m. Thursday, according to Columbus Police Chief Ricky Boren, Johnston came to the hospital with three weapons: a .32-caliber revolver, a .380-caliber semi-automatic pistol and a 9 mm semi-automatic pistol.