The British medium Francis Ward Monck was investigated by psychical researchers and discovered to be a fraud. On November 3, 1876 during the séance a sitter demanded that Monck be searched. Monck ran from the room, locked himself in another room and escaped out of a window. A pair of stuffed gloves was found in his room, as well as cheesecloth, reaching rods and other fraudulent devices in his luggage.[80] After a trial Monck was convicted for his fraudulent mediumship and was sentenced to three months in prison.[81]

After her death in the 1980s the medium Doris Stokes was accused of fraud, by author and investigator Ian Wilson. Wilson stated that Mrs Stokes planted specific people in her audience and did prior research into her sitters.[177] Rita Goold a physical medium during the 1980s was accused of fraud, by the psychical researcher Tony Cornell. He claimed she would dress up as the spirits in her séances and would play music during them which provided cover for her to change clothes.[178]
Senses used by mental mediums are sometimes defined differently from in other paranormal fields. A medium is said to have psychic abilities but not all psychics function as mediums. The term clairvoyance, for instance, may include seeing spirit and visions instilled by the spirit world. The Parapsychological Association defines "clairvoyance" as information derived directly from an external physical source.[37]