Edward William Spencer Cavendish, 10th Duke of Devonshire,, known as the Marquess of Hartington from 1908 to 1938, was a British politician. He was the head of the Devonshire branch of the House of Cavendish. He had careers with the army and in politics and was a senior freemason. His sudden death, apparently of a heart attack at the age of fifty-five, occurred in the presence of the suspected serial killer John Bodkin Adams.

John Bodkin Adams was a British general practitioner, convicted fraudster, and suspected serial killer. Between 1946 and 1956, 163 of his patients died while in comas, which was deemed to be worthy of investigation. In addition, 132 out of 310 patients had left Adams money or items in their wills.