British health authorities have confirmed that seven hotel staff have tested positive for a minor exposure to polonium-210, the radioactive substance found in Litvinenko's body.
One of the Russians that Litvinenko met at the hotel, Dmitry Kovtun, has also shown symptoms of radioactive contamination, as has another Russian whom Litvinenko met, Andrei Lugovoi.
Litvinenko, who died in London on November 23, was buried on December 7.
(compiled from agency reports)
CLOAK AND DAGGER: A timeline of a murder case that unraveled after Andrei Litvinenko, a former Russian security officer and vocal Kremlin critic, dies on November 23, 2006, of poisoning by radioactive isotope polonium-210.
In a deathbed letter, Litvinenko blames Russian President Vladimir Putin for his death -- a claim Putin condemns.
Investigators center on two meetings in London that Litvinenko had described -- one in which he met with two Russians for tea in London, and another in which he met with a third Russian at a sushi bar.
Six months later, British prosecutors announce they have enough evidence to charge a Russian citizen -- one of the men who had met with Litvinenko for tea -- with the murder ...more...
MORE: Coverage in Russian from RFE/RL's Russian Service.