One this afternoon/late morning. Mostly intact. Another ~a week ago torn to shreds.
I don't like this. Also, this seems like a cat thing as I'd expect most animals would kill and then piss off will all of their pray, instead of leaving corpses lying around...
Also, their mostly deer mice.
I really got no idea then. If you really want to figure it out you could set up a trail cam where you keep finding them?