Description:A grisly discovery in Mexico. Police found 15 bodies piled on top of each other outside a convenience store in the western state of Michoacan on Monday. The corpses, at least 13 of which were semi-naked, had been shot in what appeared to be a gang-related massacre. Local emergency services said the victims, at least three of whom were minors, showed signs of decomposition, suggesting they had been killed days earlier and then dumped outside the store.(1:16)