A British judge has ordered an inquest into the poisoning death of Aleksandr Litvinenko, a former Russian security service officer turned Kremlin critic.
The investigation is to begin in early 2013.
Litvinenko died on November 23, 2006 about three weeks after drinking tea laced with highly radioactive polonium-210.
British police have identified Andrei Lugovoi, a former FSB security agent, as the chief suspect in the murder. Litvinenko had the tea during a meeting with Lugovoi at a London hotel.
Russia refuses to extradite Lugovoi, who has been elected to Russia's lower house of parliament since the murder. Lugovoi has admitted meeting Litvinenko at the hotel, but has said he thinks the poison was meant for him.
Litvinenko's family accuses the Kremlin of being behind his death. The Russian government rejects allegations of any involvement.
Litvinenko's death severely strained British-Russian relations, leading to tit-for-tat diplomatic expulsions.
A pre-inquest hearing in London on September 20 was told that parts of a British police report on Litvinenko's ties with the British MI6 spy agency will be kept from the public at the request of the British government.
The court hearing was told the British government request "should not be taken as indicating one way or another" whether Litvinenko had dealings with the British spy agency.
A lawyer for Litvinenko's widow, Marina, told the hearing the family wants the inquest to investigate "the criminal role of the Russian state."
Judge Robert Owen, who will lead the inquest, said its scope will be determined at the next hearing -- which has been scheduled on November 2.
A Russian Foreign Ministry spokesman said Moscow expects the inquest to uncover the truth about Litvinenko's death.
Aleksandr also argued that Lugovoi already has proven his innocence by taking and passing a lie detector test.
"As far as [Andrei] Lugovoi is concerned, I think the question is closed, to a large extent, because he took a lie detector test, and I think there should be no question here," Lukashevich said. "It has been accepted by everyone and it has been shown that [Lugovoi] took that step in order to prove his innocence once again."
Under British law, an inquest is held whenever a person dies unexpectedly, violently or in disputed circumstances. It does not determine criminal liability.
Based on reporting by Reuters, AP, and AFP