At Hackney on 9 December 1873, lawyer William Volckman attended a séance held by Florence Cook, during which Katie King materialized and, as was customary, held the hands of participants. Suspicious of the spirit's similarity with Cook, Volckman seized the spirit's hand and waist, accusing it of being the medium masquerading as her ghost. The spirit was wrestled from Volckman's grasp by other participants and returned to a cabinet from which Cook emerged some minutes later. Volckman published his opinion that the spirit was a masquerade by Cook. Supporters of Miss Cook denounced Volckman on the grounds that he had broken his agreement to proper etiquette required in the séance, thus negating his credibility as an investigator: Volckman was associated with another medium, Mrs Guppy, who might have wished to denigrate her rival. Moreover, it was argued that since spirits borrowed energy and matter from their medium, it was not surprising that Katie King resembled Cook. Despite the defence of their position, Cook and her supporters were hurt by this incident — newspapers were referring to it as an "exposure" — and sought further support for their position. To this end, they turned to Crookes, who was a prominent and respected scientist.