Yeah I don't either.
A few of the photos of the girls in which the poltergeist is supposedly flinging them through the air kind of looks like them jumping but they didn't have very fast movement detection cameras back in the 70s so the movements were to far apart to really tell what happened.
Lot's of witnesses saw things happening including police but the freakiest thing of all is listening to the voice of the poltergeist or the voice that the girl is putting on, scary!!
Cheers
Ben