Spy death linked to nuclear thefts--rules out "lone assassin"

An investigation was under way last night into Russia's black market trade in radioactive materials amid concern that significant quantities of polonium 210, the substance that killed former spy Alexander Litvinenko, are being stolen from poorly protected Russian nuclear sites.

As British police drew up a list of witnesses for questioning over the death, experts warned that thefts from nuclear facilities in the former Soviet Union were a major problem.

A senior source at the United Nations nuclear inspectorate, the International Atomic Energy Agency, told The Observer he had no doubt that the killing of Litvinenko was an 'organised operation' which bore all the hallmarks of a foreign intelligence agency. The expert in radioactive materials said the ability to obtain polonium 210 and the knowledge needed to use it to kill Litvinenko meant that the attack could not have been carried out by a 'lone assassin'.