| Clue | Source | Date |
|---|---|---|
| Retiring President about to regret poisoning agent | The Telegraph Toughie | 29 Nov 2019 |
| A poison which is destructive to nerve tissue | The Times Specialist Sunday | 21 Apr 2019 |
| Nerve poison? It could be true in Oxon | The Telegraph Toughie | 04 Sep 2018 |