[TOMT] ghost story about a ghost helping a young girl wash her hands

Girl is sent to bathroom to wash her hands even though she wasn't tall enough to reach the sink. She comes back with clean hands and her family is taken by surprise. The girl says a naked lady with long hair held her up while she washed. But there's no lady to be found. Later on, they look up the history of the house and realize a woman had been murdered in the bathroom. I was told this story and am looking for the source