— 2000: Litvinenko flees Russia and seeks political asylum in Britain, which was granted the following year.
— 2002: Litvinenko co-writes a book in which he accuses his former FSB superiors of carrying out a number of Russian apartment block bombings in 1999, which were blamed on Chechen militants.
— Nov. 1, 2006: Litvinenko falls violently ill after drinking tea with two Russian men, Andrei Lugovoi and Dmitry Kovtun, at the Millenium Hotel in London.
— Nov. 20, 2006: The Kremlin dismisses allegations that Russia's government poisoned Litvinenko as "sheer nonsense."
— Nov. 23, 2006: Litvinenko dies at 43 after a heart attack in London's University College Hospital. A day later Litvinenko's family releases a statement accusing Putin of involvement in his death. His death is blamed on poisoning from radioactive polonium-210.
— 2007: British prosecutors charge Lugovoi, an ex-FSB agent, with murder, but Moscow refuses to extradite him. As a result of the tussle, Britain and Russia both expel embassy staff and diplomatic relations drop to a low.
— 2013: An inquest into Litvinenko's killing — the usual method of examining an unexplained death — is stalled after it was barred from considering secret evidence about the possible role of the Russian state.
— July 2014: Britain announces that in place of an inquest, Judge Robert Owen will instead chair a public inquiry into Litvinenko's death.
— Jan. 2015: The inquiry opens. Owen holds 34 days of public hearings and also looks at secret intelligence evidence behind closed doors.
— Jan. 21, 2016: The inquiry report is published. Judge Owen says there was a "strong probability" that the FSB directed the killing of Litvinenko and that the operation was "probably approved" by Putin.
(AP)