Police in Britain say they are now treating the death of Alexander Litvinenko as murder.
The former KGB agent died in a London hospital after ingesting a large dose of the radioactive substance polonium-210.
On his death bed, 43-year-old Litvinenko accused Russian president Vladimir Putin of being behind his poisoning.
Scotland Yard is stressing they have not reached any conclusions as to the means employed, or the motive, or the identity of those who might have been responsible for Mr Litvinenko's death.
