The German magazine Focus has published a report which asserts that two days before Litvinenko was poisoned, a Russian diplomat in London died under mysterious circumstances, after apparently being poisoned by a radiological attack.
AIA has a synopsis of the article [some editing]:
Last autumn Igor Ponomarev, representative of Russia in the International Maritime Organization (IMO), died in the British capital. Focus writes that the diplomat was attending a theatre performance when he suddenly felt bad, xperiencing a strong attack of thirst. The Russian had drunk a few litres of water, and had subsequently died. The cause of his death was declared to be a heart attack. His body was quickly delivered to Russia, although no post-mortem examination was made.
Sudden thirst is not known as a symptom of heart attack, according to Dietrich Andresen from the German Society of Cardiologists. Gabriela Gerber-Zupan from the Poisoning Emergency Centre in Munich, told Focus that in the expert toxicologists' opinion, thallium (which was initially also thought to be the cause of Alexander Litvinenko’s poisoning) might cause a thirst of this kind. Igor Ponomarev wanted to be at the appointment with the Russian ex-security officer along with Litvinenko’s Italian contact, Mario Scaramella. However, according to his relatives he died a day before the planned meeting on October 30, 2006.
According to Focus, Ponomarev’s relatives do not exclude the possibility that the death of the Russian diplomat is connected with the case of the poisoning of the former FSB officer. Scotland Yard did not launch an inquiry into the causes of the Russian diplomat's death as, according to its spokesman, no one had applied for such an inquiry to be opened.