They stated they found the body. So its not using its skin. But its way of killing identifies with a spider.. Some spiders inject poison into its pray which turns the inside to mush, then they drink it.... So yeah.. its highly suspicious as the work of a spider. But I doubt police are thinking the same thing at this point 
Nevermind, her body was highly destroyed, but it wasnt completely destroyed, they were still able to do autopsy. So I cant be sure how the spider is appearing in an undamaged body..