A physician in the afterlife who called himself Dr. Doherty came through in a seance in 1965. He explained that, after his death, he couldn't reconcile himself to being dead and paced through the house banging on things and throwing objects about. Those in the house were alarmed at the manifestations and thought it was a poltergeist. Eventually, he realized that his ranting wasn't helping him communicate, and he left.
Listen to Dr. Doherty describe his poltergeist activity