Policing as we know it wasn’t really a thing until relatively recently (around the turn of the 20th century). Before that, case files didn’t really exist. So yeah, you might be right, but they can only go off of what’s been reported. It’s very rare for a body to be left with no identifying characteristics like this woman’s. The FBI keeps a list of unidentified victims and they only have 53 of them in the whole country.