So, this is super vague and I apologize, but something sparked my memory and it's been bothering me, so here goes...
I'm looking for a young-adult book I read probably in the early 2000's. It was possibly older than that, but I doubt it was earlier than the seventies or so, and was likely somewhere in my elementary school. I have no information as to what was on the cover.
In terms of plot, I think it involved a haunting of an old house and two (or maybe three) children. Either the older or middle one was a girl of twelve or fourteen. When the ghost/spirit/whatever starts moving things and causing havoc in the house, I think the parents call a doctor. He turns out to be a sinister-type character who wants to take the girl away, believing her to be the source of the disturbances. I think the ghost or whatever takes a liking to the kids and tries to help, but for some reason I don't think it can talk or manifest, only move things.
I know it's not much to go on, but it's been on my mind all day. Any help would b great!