I don't think it is a raccoon or my dog would have been killed or at the best, really torn up. I can't imagine any trapped raccoon, even a just weaned baby, wouldn't make mince meat out of an 8 pound little dog. I thought opossum or maybe even baby skunks before they've developed scent, but I can't imagine skunk. Where was mama? If it was a skunk den I would think mama would leave some odor around even if she wasn't there--and the only reason that would be was because she had died somewhere else. And it sounded pretty big banging up against the walls. I think opossum. It huffed, too, and I think opossums and skunks make that huffing sound when they are scared.
The only damage whatever it is is doing is eating tomatoes and my cantaloupe, which isn't the end of the world. Makes my husband crazy, but I have more tomatoes (or I did) than I can eat so don't mind sharing.
I want to get a livestock guard dog when these Dachshunds are all gone. I've too many dogs--the four Dachshunds and a big putbull kind of mutt.