a city blighted bugged

the Treviso: A City Blighted quest is bugged. The corpse of the darkspawn that needs to be investigated is all the way in the corner of the map in my game. I cannot access it to complete the quest. I would love to know a way to either reset/complete the quest. When fighting the darkspawn I was using the Evoker skills that push enemies away and stuff. It died while in an entropic sphere I cast at it. Playing on PC/Steam.