The Italian security expert who met former Russian spy Alexander Litvinenko on the day he fell fatally ill was released from a London hospital Wednesday after showing no signs of radiation poisoning.

Authorities on Wednesday also announced that traces of radiation had been found at a London soccer stadium and at the British Embassy in Moscow, and British police said they are treating Litvinenko's death as murder.

The expert, Mario Scaramella, was discharged and was in good health, University College Hospital spokesman Ian Lloyd said. Scaramella was admitted to the hospital after testing positive for polonium-210, which was found in Litvinenko's body.

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A British official also said faint levels of the same element had been found at two locations at London's Emirates Stadium, where a key figure in the investigation, former Russian agent Andrei Lugovoi, attended a soccer match on Nov. 1.

The radiation was "barely detectable" and posed no public health risk, said Katherine Lewis, spokeswoman for the Health Protection Agency.

Traces also were found at the British Embassy in Moscow, the Foreign Office said. Officials said the level was low and posed no risk to health.

The agency has been tracking a number of sites found to be contaminated with the deadly element, including a sushi bar and a hotel Litvinenko visited on Nov. 1, the day he reported feeling sick. He died in a London hospital on Nov. 23.

The restaurant, Itsu Sushi, said Wednesday that it would reopen in the new year. It said all its staff had been given a clean bill of health.

Lugovoi, who is now hospitalized in Moscow for tests for possible radiation contamination, attended a match at Emirates Stadium between CSKA Moscow and Arsenal on Nov. 1, the same day he met Litvinenko.

A former KGB officer, Lugovoi told Ekho Moskvy radio in Moscow that he had known Litvinenko for a decade, dating back to Lugovoi's tenure as head of security for ORT television, which was controlled at the time by tycoon Boris Berezovsky, who now lives in London.

He said Litvinenko had contacted him from London about a year ago with some business-related proposals, and that they had met intermittently in London since then.

One of Lugovoi's business associates, Vyacheslav Sokolenko, said British investigators were due to meet with Lugovoi on Wednesday. But ITAR-Tass quoted a lawyer for Lugovoi, Andrei Romashov, as saying the meeting with Scotland Yard detectives would take place either Thursday or Friday.

"Representatives of law enforcement agencies have not notified us of a date or time," Romashov was quoted as saying.

ABC News reported that British detectives had identified Lugovoi as a prime suspect in Litvinenko's poisoning. The report cited an unidentified senior British official.

British police have publicly named Lugovoi only as a witness. A British government official, who requested anonymity because he is not authorized to speak to the press, said Lugovoi was "one of many people investigators are looking to question but I wouldn't call him a suspect at this point."

"We're also looking at the possibility there were criminal gangs involved," he said. "I think the investigation will take a very long time but I doubt any one person will be named or implicated in the end."

Lugovoi told the ITAR-Tass news agency that he was undergoing special tests for possible radiation contamination, and that the results would be ready in a few days.

He said he was prepared to answer all the British investigators' questions.

"I intend to fully satisfy their interest and am waiting for an invitation from the law enforcement organs," he was quoted as saying.

"Once I give all the necessary testimony to the law enforcement organs, I intend to publicly put an end to [speculation] about my supposed involvement in this story that has caused such a stir," he said.

Lugovoi traveled to London three times in the month before Litvinenko's death and met with Litvinenko four times, according to Russian media.

Litvinenko's funeral is expected to take place before the end of the week.

His father Walter told Radio Liberty that his son had converted and wished to receive a Muslim burial.

"He told me about his decision two days before he died. He said, 'Papa, I have to talk to you about something serious. I've become a Muslim."'

An ally of the dead man said the ex-spy had converted to Islam on his deathbed.

"He told me that he wanted to convert to Islam literally in his first days in the hospital," said Chechen rebel envoy Akhmed Zakayev.

"I did not pay a lot of attention to this," Zakayev told Radio Liberty, "but he returned to the theme again and again."

Zakayev said that on Nov. 22, the day before he died, Litvinenko was visited in hospital by an imam, who read a Koranic verse traditionally said over the dying.

Litvinenko's friend Alex Goldfarb confirmed an imam had visited him in the hospital, "when he was heavily sedated and on the verge of death."

He said he did not know whether his friend had converted.

"He was basically a non-religious person as long as I knew him," Goldfarb said.