A spate of murders gained this element the moniker of "poisoner's poison", as it is colorless, tasteless and odorless, and causes symptoms in the victims which can easily be attributed to other causes. It featured in an Agatha Christie novel, The Pale Horse; a major clue was hair loss, a distinctive side effect.
Have you guessed today's poison? It's Thallium.
During 1952-1953 several successive murder trials featured thallium poisoning in Australia; chronic vermin infestations, the easy availability of thallium rat poison and the human propensity to "copy-cat" probably led to the cluster of killings. There were 5 different murder cases during that time period. The most sensational was probably that of Veronica Monty in 1952; she was tried for the attempted murder of her son-in-law and rugby player Bob Lulham, and the trial revealed that she had been involved in an intimate relationship with him. Veronica was found not guilty, but committed suicide - using thallium - in 1955.
Other noted cases include:
- 1957 Nikolai Khokhlov, a former KGB assassin, was poisoned with thallium. (Oh, the irony.) He was eventually flown to the US and recovered.
- 1971 Graham Frederick Young used thallium to poison around 70 people in the English village of Bovingdon. Three died.
- 1988 George J. Trepal, later known as "The Mensa Murderer", was convicted of poisoning his neighbors the Carrs by placing Coke bottles laced with thallium nitrate in the residence. The mother, Peggy Carr, died; the rest of the family was sickened but survived. It seems that George was annoyed with his neighbors, especially because they were too loud. He may have been brilliant and a member of Mensa, but he made two very stupid mistakes. He couldn't keep his mouth shut; he drew suspicion when he attended a Mensa group murder weekend and said something about "neighbors needing to watch what they eat/drink around the house". And, he didn't get rid of the evidence; a vial containing traces of thallium was found in his garbage.