From what you describe, they sound like poached deer to me considering the limited butcher job. Is this trail where somebody could hear the gunshots?
Suggestion: If you ever see someone with a rifle around that area, and that you believe is poaching, I'd just call 911 and tell them the truth, that being there is someone walking around with a firearm on a trail frequently used by kids. Don't even mess with the DEM. Believe me, you'll have law enforcement there in a big hurry, and if they're up to no good the cops will find out.
Got no problem with legal hunters, but poachers..that's different.