They didn't mention Nancy Moyer in that article. There is a possibility it is her.
You are correct. I am not from Washington, but the New York area, so I had never heard of the Nancy Moyer case, but I found it here.
She was from the Olympia, WA area too, so yes, you are right, it could well be she, and not Shantina.
http://abcnews.go.com/US/story?id=7151744&page=1