Subsequent forensic enquiries revealed the thallium poisoning: the first recorded case of deliberate poisoning by this heavy metal ever recorded. Young’s poison conviction was soon unearthed, as were his collection of poisons, and meticulous diaries recording explicit dosages administered to individuals, and their reactions to the dosage over time.
Young was arrested in Sheerness, Kent, on 21 November 1971, where he had been visiting his father. A quantity of thallium was found on his person. Under interrogation, he admitted verbally to the poisonings, but refused to sign a written admission of guilt. He clearly relished the notoriety that his day in court would afford him.