An acquaintance visited the house and said that it was really scary there. However, from watching various documentaries and reading loads about the case I'm doubtful much of it was real. The girls admitted that they faked some of it (although, I can't find the documentary that this was in, but I remember it!).
The photos of Janet "levitating" are clearly her jumping, you can see by the position of her body.
I suppose, as I grew up nearby it was always something that interested me.