Bad Blood

Bad Blood begins with an accident of war that is harder to see than a murder. A secret British biological warfare experiment with anthrax becomes dangerous when an infected sheep carcass is lost in transit, and in Hastings, meanwhile, a Quaker conscientious objector named Martin Ashford stands accused of killing Thomas Jenkins, a holder of the Distinguished Service Medal and a survivor of the Navarino, a ship sunk in Convoy PQ 17. Ashford's sister Edith, now a nurse and a school friend of Milner, asks him to help her brother, and Foyle agrees to look into the case. His presence in nearby Hythe irritates his old colleague DCS David Fielding, who regards the ground as his own.

The enquiries show that Ashford and Jenkins had quarrelled in a local pub about Ashford's conscientious objection and about his affair with Jenkins's wife, Elsie. Foyle also works the theft of cattle from Foxhall Farm, which belongs to Brian Jones, Jenkins's father-in-law and the man Ashford laboured for. Fielding hands Foyle the murder weapon, a trocar that belongs to the veterinarian Ted Cartwright and was apparently lost at Foxhall Farm, but Cartwright's son Leonard has already told Fielding that Ashford could not have killed Jenkins, so the weapon and the alibi point in opposite directions. Both Elsie Jenkins and Sam Stewart become infected with anthrax, and a second Quaker, Henry Styles, who has been watching Foxhall Farm, directs Foyle to Captain George Halliday, the officer commanding the secret anthrax research facility, and to an assistant researcher, Mark Wilcox.

The resolution joins the two cases to the same small patch of country. The killer is Leonard Cartwright, Ted Cartwright's son. Leonard had also survived the sinking of the Navarino, even though Jenkins had shot him, and he killed Jenkins to put a stop to his bullying and his duplicity. The accused man, Martin Ashford, is cleared. The farm, the theft, the research station and the killing sit within sight of one another, and the episode's moral ground is the immunity that secrecy buys, since the facility cannot be discussed and the investigation has to work around what it is not allowed to know.

The strength is that joining: a biological warfare accident and a murder become one investigation, so that each explains the other, and the conscientious objector is the instrument of the piece, because the man the town has decided is guilty is the one man in the story who refuses the war, while the actual killer is a survivor of a sinking the victim caused. Gawn Grainger's David Fielding is the second centre of gravity, an old colleague and fellow veteran of the First World War kept at a distance that has a history, and his remark about bad blood follows his survival of a chlorine gas attack at the Second Battle of Ypres. The murder weapon, a veterinary instrument used by a man who had reason to hate his victim, inverts the expected class of suspect.

The weakness is the pacing: the anthrax facility and the murder are kept apart for long enough that the middle of the episode runs two cases that do not obviously connect. One production note belongs with the record, the reported cameo by the real Christopher Foyle, the chairman of the booksellers whose name supplied the detective; the account of it is a short exchange that does not advance the plot, and it is said to have been cut from the American transmission. The episode closes Series 4 Part 1.