Sergeant Royston from Scotland Yard to investigate the murder, suspects that the star was placed on the body to divert attention towards David. Equally skeptical is David's wife Lucy, the daughter of estate owner Lord Eversley, who notes the tension between Thirke's newly-pregnant wife, Angela, and Angela's sister, Daphne, who was having an affair with Thirke. As Carmichael begins his investigation, he requests the assembled guests to remain at the house. Chafing at the oppressive atmosphere, Lucy accepts an offer from her father to go riding, but while they are out, they are attacked by a young man, who shoots at them with a rifle before he is killed by Lord Eversley. An inspection of the body uncovers a membership card identifying him as a communist and an identity card for an Alan Brown, which is different from the name on the party identity card. Carmichael is puzzled by the incident, which appears to be unconnected to Thirke's murder. As pressure grows for Carmichael to release the guests, a search of the Kahns' apartment turns up letters that offer evidence of David's involvement with an underground Jewish organization, which sought the murder of Thirke and the other members of the "Farthing Set". Aware that an arrest would mean the effective conviction of David but still not convinced of his guilt, Carmichael convinces him to remain at Farthing House under police supervision. Returning to London, Carmichael is given until Friday to conclude the case. His ability to act is further hampered by the political situation since Daphne's husband, Mark Normanby, the Foreign Secretary and one of the guests in Farthing House, emerges from the cabinet shuffle as Prime Minister. Exploiting both Thirke's murder and the shooting incident, Normanby announces the introduction of identity cards, the expulsion of foreign nationals, the banning of communists and a delay in the general election. Resisting political pressure to arrest David, Carmichael pursues his investigation of Angela and discovers that her baby was likely the result of an affair with the family's chauffeur. Locating Brown's girlfriend, an Agnes Timms, in Southend-on-Sea, Carmichael travels there with Royston to interview the young woman and discovers that Brown was approached by Angela to stage the attack on Lord Eversley, ostensibly as a joke. Returning to London, Carmichael learns that the yellow star was purchased by someone who claimed to be David. With a warrant now issued to arrest David,