http://www.reuters.com/article/idUSTRE6BA2OV20101211(Reuters) - Russian authorities were following the suspected killers of Alexander Litvinenko, the former Russian agent murdered in London four years ago, but were told by Britain the matter was under control, according to a U.S. diplomatic cable released by WikiLeaks on Saturday.
Former KGB agent Litvinenko, who lived and worked in Britain, was poisoned in November 2006 using the highly toxic polonium-210, a rare radioactive isotope, with his associates blaming Russian agents for his death.
His death soured relations between Britain and Russia to a post-Cold War low, and London has called on Moscow to extradite former KGB bodyguard Andrei Lugovoy to stand trial for murder.
Russia has refused and Lugovoy, who was later elected to the Russian parliament giving him immunity from prosecution, denies any link to the death.
According to the leaked secret U.S. cable published on the Guardian newspaper website, a Russian official said shortly after Litvinenko's death that Russia had been tracking the dissident's assassins and had also indicated that the Kremlin had not been involved in the murder.