In the 1930s the psychologist and parapsychologist Nandor Fodor advanced the theory that some poltergeist disturbances were caused not by spirits but by human agents suffering from intense repressed anger, hostility, and sexual tension. Fodor successfully demonstrated his theory in several cases, including the most famous "Thormton Heath Poltergeist" in England, which he investigated in 1938. The case involved a woman whose repressions caused a poltergeist outbreak and apparently a vampire attack. The Spiritualists severely criticized Fodor, but he won a libel suit against a Spiritualist newspaper.