LONDON — One day in 2006, a former KGB agent who claimed to know dark Kremlin secrets had tea with two Russian men at a London hotel. Three weeks later, he died of radioactive poisoning — after making a deathbed claim that Russian President Vladimir Putin had ordered his killing.
Moscow has always denied involvement, and almost a decade on, no one has been brought to justice.
On Thursday, British judge Robert Owen will release the long-awaited findings of a public inquiry into the killing of Litvinenko — and is likely to point a finger at elements in the Russian state.
WHO WAS ALEXANDER LITVINENKO?
Litvinenko's widow, Marina, told Owen's inquiry that her husband was a loyal intelligence agent who grew disillusioned with Russia's 1990s war in Chechnya and by what he saw as corruption within the FSB security service, successor to the KGB.
He fled to Britain in 2000 and was granted asylum, becoming a vocal critic of Putin and his allies.
When Litvinenko became violently ill in November 2006 at the age of 44, doctors were baffled. The cause would likely have remained a mystery were it not for a urine test conducted by a doctor, on a hunch, shortly before Litvinenko died. It revealed the presence of polonium-210, an isotope that is deadly if ingested in tiny quantities.
Litvinenko's body was so radioactive that the autopsy was conducted by medics in protective clothing and ventilation hoods. A lawyer for the police said the killing may have exposed hundreds or even thousands of Londoners to radioactive contamination.
WHO KILLED HIM?
British police have accused Dmitry Kovtun and Andrei Lugovoi, the two Russians Litvinenko met for tea, of carrying out the killing, sponsored by elements in the Kremlin. Both deny involvement, and Moscow refuses to extradite them.
British detectives and scientists told the inquiry that a radioactive trail was left at hotels, restaurants and other sites across London visited by Kovtun and Lugovoi, a former FSB agent who is now a Russian lawmaker and was decorated by Putin for services to the nation.
Many Russian officials had reason to dislike Litvinenko. His family says he was working for MI6, Britain's foreign intelligence service. He had accused the Russian government of involvement in a series of apartment building explosions in 1999 that were blamed on Chechen rebels, and alleged links between senior Kremlin figures and organized crime.
WHAT WILL THE JUDGE SAY?
Owen heard from 62 witnesses over six months of public hearings and — behind closed doors — saw secret intelligence evidence about Litvinenko and his links to U.K. spy agencies.
The judge is likely to name Lugovoi and Kovtun as the culprits, and says he has seen evidence of Russian state involvement. The big question is whether he will name Putin or people close to him as ordering the killing.
John Lough, a Russia expert at the Chatham House think tank, said that Russia's "opaque" political system made it unlikely that Owen would be able to name names.
"It seems very likely that the judge will conclude that there was the involvement of Russian state agencies, but I rather doubt that he'll be able to be more specific," Lough said.
WHAT COULD THE REACTION BE?
Litvinenko's death soured British-Russian relations for years, and Russian involvement in Ukraine's civil conflict made things even worse, bringing sanctions on Moscow by Western countries including Britain.
A finding of direct involvement in the killing by senior Russians could cause a further deterioration.
But Owen's report comes as Russia and Britain are both involved in airstrikes against the Islamic State group in Syria. British diplomats believe Russia — an ally of Syrian President Bashar Assad — is key to ending that country's brutal civil war. Russia, its economy hurt by low oil prices, would like to see an end to sanctions.
It may be in the interests of both Britain and Russia to limit the fallout from the Litvinenko killing.
In any case, there may be little Britain can do to influence behavior in the Kremlin. The Soviet-era KGB didn't hesitate to kill its enemies on foreign soil, sometimes with obscure poisons — Bulgarian dissident Georgi Markov died after he was stabbed with a ricin-tipped umbrella on London's Waterloo Bridge in 1978. Some believe the Kremlin's attitude to opponents has changed little.
Lough noted that Putin allegedly once told a Russian journalist "that he distinguished between enemies and traitors."
"He said that with enemies you can find a common language and agree on things, but in the case of traitors, they need to be liquidated."
Follow Jill Lawless on Twitter at http://Twitter.com/JillLawless