British authorities investigated the death and it was reported on 1 December that scientists at the Atomic Weapons Establishment had traced the source of the polonium to a nuclear power plant in Russia.
Pemerintah Britania menyelidiki kasus kematiannya dan dialporkan pada 1 Desember bahwa para ilmuwan di Atomic Weapons Establishment Britania telah menelusuri sumber poloniumnya ke sebuah pembangkit tenaga listrik di Rusia.