A businessman who met Alexander Litvinenko at the London hotel where he is believed to have been poisoned was interviewed for the first time yesterday by Russian and British detectives.
Vyacheslav Sokolenko, 37, an associate of two men at the centre of the murder case, is the latest witness to be questioned about the fatal radiation dose ingested by Mr Litvinenko on 1 November.
Mr Sokolenko, a private security officer, was interviewed in Moscow.
He met Mr Litvinenko at Mayfair's Millennium Hotel, along with two Russian contacts, Andrei Lugovoi, and Dmitry Kovtun, on the day the former spy fell ill. Mr Litvinenko died on 23 November.
Scotland Yard officers believe that Mr Litvinenko's first contamination from radioactive polonium-210 was at a sushi bar in central London where he met an Italian contact called Mario Scaramella.
He then met the three Russian men. It was during this meeting that police believe Mr Litvinenko may have been given a second dose of radiation poisoning.
Mr Sokolenko, who used to work in the Federal Guard Service which provides security for senior state officials, said he did not know Mr Litvinenko, and had gone to watch Arsenal play the Russian side, CSKA Moscow, in London with Mr Lugovoi.
Scotland Yard has described Mr Lugovoi as a "significant witness" in the inquiry. Yesterday he insisted that allegations that he could have been behind the poisoning were nothing more than "hysteria".
"I am not regarded as a suspect, I am regarded as a witness, police are not accusing me of anything," Mr Lugovoi said. "As for all that is being said - it's nothing but hysteria in the media.I will respond to all my critics after the investigation is over."Reuse content