My first deer died the same way. . .I shot at a doe and she took off like a speeding bullet, low to the ground and fast. . .took a shot at her on the run and missed again. . .one round left in the Remington 1100 and I turn around and there is a deer just standing there about 75 yards away looking at us and not doing anything. . .I take my time, aim and it drops instantly. . .no thrashing or anything. . .we get to it and we can't find an entrance hole, exit hole, or any blood, but it was definitely dead. . .and you would think that if it got hit with a 3" 12 ga. slug that you would be able to figure out where it got hit!!!
I was hunting in Illinois so there is no rifle season. . .only slug gun, bow, handgun, and black powder seasons. . .