It's hard to tell on the first picture, but the shot placement looks back. Also hard to tell if the shot went forward into the lung cavity or back into the intestines. Also cannot tell if that's an entrance or an exit wound shown; i.e. exit shot from above or entrance wound from ground level.
My point is, with a shot that far back, that deer could have walked a half mile or more (maybe a mile) before expiring on your property. Maybe none of your immediate neighbors are to blame (not that I'm blaming anyone).
That dead buck is just an unfortunate part of hunting. At the very least you were able to salvage the antlers - and maybe some meat - and wasn't all for waste. Hopefully a buck that beautiful got to seed his DNA around, a lot!!
One day my ship will come in!! My luck, I'll be at the airport.