LONDON — Alexander Litvinenko, the former KGB agent at the center of an international poisoning mystery, was buried here Thursday, his body still so radioactive that health officials wouldn't let it be displayed at a memorial service.
As friends and colleagues gathered to recite eulogies, sing hymns and, once again, denounce the Russian government -- which many blame for his death -- the intrigue picked up yet another layer: The Russian news agency Interfax announced that a key witness and possible suspect in the case had fallen into a coma in a Moscow hospital hours after being questioned by British investigators.
A lawyer involved in the case denied the report.
The witness, Russian businessman Dmitry Kovtun, appears to be the most gravely ill of a lengthening list of people contaminated by polonium-210, the radioactive isotope that British police think was used to kill Litvinenko last month.
As the investigation of Litvinenko's poisoning has progressed, British police have remained silent on almost all questions.
One thing British authorities have spoken about openly is the discovery of traces of polonium-210 at many of the places visited by key players in the drama.
That includes a restaurant where Litvinenko, 43, lunched on sushi Nov. 1 while meeting one of his contacts, the Italian security consultant Mario Scaramella. The Italian has tested positive for "significant quantities" of polonium but appears to be in good health.
The venues also include the Pine Bar in the Millennium Hotel in London, where Litvinenko met for tea later that day with Kovtun and a second Russian businessman, Andrei Lugovoy. Lugovoy is hospitalized in Moscow and believed to be undergoing checks for radiation contamination.
Seven employees at the Pine Bar appear to have been exposed to low levels of polonium-210, prompting health authorities to invite customers to be tested for radiation.
"There's no health risk in the short term. They're not sick. In the long term, the risk is judged to be very small," said Siovhan Leigh-Hunt, a spokeswoman for Britain's Health Protection Agency.
The levels found in the bar employees were thought to be lower than those found in Litvinenko's wife, who also has been contaminated but has shown no signs of illness.
As a "precautionary approach," authorities are asking patrons who visited the bar Oct. 31 through Nov. 2 to come in for testing, Leigh-Hunt said.
