The Irvings' claims gained the attention of parapsychologists and ghost hunters, such as Harry Price, Hereward Carrington, and Nandor Fodor.
In September 1931, the Irving family, consisting of James, Margaret, and a 13-year-old daughter named Voirrey, claimed they heard persistent scratching, rustling, and vocal noises behind their farmhouse's wooden wall panels that variously resembled a ferret, a dog, or a baby.
According to the Irvings' words, they gave Gef biscuits, chocolates, and bananas, with food left for him in a saucer suspended from the ceiling which he took when he thought no one was watching.
[6] Price asked Reginald Pocock of the Natural History Museum to evaluate pawprints allegedly made by Gef in plasticene together with an impression of his supposed tooth marks.
[3] The diaries of James Irving, along with reports about the case, are in Harry Price's archives in the Senate House Library, University of London.
Fodor disbelieved any deliberate deception had occurred and moulded a complex psychological theory to explain Gef based on "a split-off part" of Jim Irving's personality.
[9] Although some psychic investigators thought that Gef was a poltergeist or another type of ghost, sceptics, including residents of the Isle of Man, believed the Irving family had colluded to perpetuate a hoax that was originated by daughter Voirrey.
[10] According to Joe Nickell researchers have suspected Voirrey used ventriloquism and other tricks "the effects of which were hyped by family members, reporters in search of a story, and credulous paranormalists.