A coroner overseeing a British inquest into the poisoning death of a former Russian security agent has ruled that he can't consider evidence on whether the Russian state was involved in the killing.
Robert Owen said he accepted an application made by British Foreign Secretary William Hague to keep some evidence surrounding the case of Alexander Litvinenko secret.
The decision adds further doubts to an already much-delayed inquest into the Russian's 2006 death. Litvinenko, a former agent turned Kremlin critic, died after drinking tea laced with the radioactive isotope polonium-210 at a London hotel.
In his ruling, published Friday, Owen said he agreed to Hague's request to exclude evidence surrounding the role of the Russian state in the killing and whether Britain could have prevented the death.