A domestic dog is the only thing I can think of that would kill just to kill. Cats will usually eat the organs (my cats favorite are the brains and eyes).
Fox or coyote would have taken the carcass, but often raccoons will take just the choice stuff and leave the rest. Sometimes it is the head, other times the insides.
Was it evicerated? No idea, I didn't inspect it taking the pic was about as close to the injury as I got
Weasels, opossum, hawks, and owls can also take birds and eat the choice parts as well, specially if it didn't get inside the coop and tried to roost in a nearby tree, which Guineas are famous for.
Sorry it happened.
My mom called me earlier when she got home and I thought she knew already, so I was actually nervous answering the phone lol. Chrissy told her later, apparently she took it very well, probably better then me. I was a little teary when I was bagging up the body and putting her in the freezer and my friend Nikki called me, since I don't talk to her often I answered and I guess she could hear I was upset, so when she asked what was wrong I lost it and started sobbing . It's not even like the guinea hens are friendly lol. She was always my favorite tho, such a pretty color, and she was so cute as a chick, I was always holding her(you would think she would have been friendlier)