LONDON — British authorities Wednesday formally classified the recent poisoning death of a dissident former Russian spy as a murder case, changing it from the category of a suspicious death.
Alexander Litvinenko is believed to have been poisoned with radioactive polonium-210, probably on Nov. 1, when he met with several people in London.
British and Russian investigators questioned one of those people, Russian businessman Dmitry Kovtun, at a Moscow hospital Wednesday, where he apparently was undergoing testing for radiation. The questioning of a second businessman, Andrei Lugovoy, who attended the same meeting with Litvinenko and is also hospitalized, was put off until at least today.
Both men have been viewed as key witnesses and potential suspects.
Police are pursuing "many lines of inquiry" in both Britain and Russia and have interviewed a number of witnesses, a statement from London's Metropolitan Police said.
"Detectives investigating the death of Alexander Litvinenko have reached the stage where it is felt appropriate to treat it as an allegation of murder," the statement said.
"Detectives in this case are keeping an open mind and methodically following the evidence," the statement said. "It is important to stress that we have reached no conclusions as to the means employed, the motive or the identity of those who might be responsible for Mr. Litvinenko's death."
Among Litvinenko's close friends in London was Akhmed Zakayev, the foreign minister in Chechnya's self-declared separatist government, whom the Kremlin considers a terrorist. Zakayev said Wednesday that Litvinenko converted to Islam as he was dying, and that a Muslim funeral would be held for him today in a London mosque.
Litvinenko's body will not be present at the mosque because of safety concerns related to polonium-210. Instead it will be taken directly to a cemetery for burial, Zakayev said.
Doctors have found that Mario Scaramella, an Italian security consultant who met Litvinenko Nov. 1 at a London sushi restaurant, also has significant quantities of polonium-210 in his body. Scaramella was released from a London hospital Wednesday in apparent good health.
The British Foreign Office announced that small traces of radiation had been found at the British Embassy in Moscow.
Lugovoy visited the embassy early in the investigation to offer cooperation and deny any involvement in Litvinenko's poisoning. The visit triggered the building's examination.
British officials said a team of experts had conducted checks on the embassy, detecting small traces of radiation not considered a health risk.
While investigators were questioning Kovtun, Lugovoy spoke with the Russian news agency Interfax and expressed a willingness to cooperate.
"Currently they are talking to my business partner Dmitry Kovtun, who is undergoing a medical examination at the same hospital as myself," Lugovoy said. "I cannot exclude the possibility that, after talking to my partner, the investigators will decide to talk to me as well. I want to repeat again that I have never refused to meet with British investigators."
Lugovoy also expressed anger over becoming a target of speculation in media reports.
"As for the hullabaloo about me that has been stirred by Western media, in my view good theatrical directing is traceable here," he said.
"I've stopped watching television and reading papers. I'm fed up with all this."
Lugovoy's lawyer, Andrei Romashov, told Interfax that British investigators had said they wanted to question his client as a witness, not a suspect.
In Britain, health officials have found traces of radiation at about 14 locations in London, including Emirates Stadium in North London, where Lugovoy and a large number of other Russians attended a soccer match Nov. 1 between Moscow's CSKA team and London's Arsenal.
British Health Protection Agency spokeswoman Alex Baker said tests on a certain part of the stadium had been conducted at the request of Scotland Yard and confirmed "barely detectable" levels of a radioactive substance.
"We determined there was no risk to public health, and we made that clear," she said.
Health officials have not identified the substance as polonium-210, but they emphasized that the element is present in very small quantities in the human body and elsewhere.
"It's a naturally occurring element. It's in the environment. What we look for is if there's any risk to public health. We found that levels did not meet that requirement," Baker said.
Kelly Classic, an expert on radiation safety at the Mayo Clinic in Rochester, Minn., said it was likely that radiation levels would have to be higher than normal to trigger positive readings.
"If I just surveyed my office and all over the place here, I really wouldn't expect to see polonium," she said. "So when they're finding trace amounts -- and I haven't seen them admit it's polonium, but we could assume that it is -- I would assume that it's extra, it was something that was brought there, left there, put there."