Could it have been like that movie 'The Other'?
In case anyone doesn't remember The Other, it was a book and then a movie about a set of twins who end up doing some serious damage. SPOILER - if you don't want to know about the book, stop now.
Anyhoo, it turns out the one twin died, and the other one has been either possessed by him or had multiple personality disorder. But, in the movie, you see both twins because the living one still feels and see the other (hence, the title). Could this movie be the same in that the living daughter does all the killing but you think it's the dead daughter?
What do you guys think?
The gene pool could use a little chlorine......