CPS names second suspect in Alexander Litvinenko poisoning Mr Kovtun was with Andrei Lugovoi, the chief suspect in the murder, when the pair met Litvinenko in the Pine Bar of the Millennium Hotel in Mayfair on November 1, 2006. That was the moment when detectives believe a lethal dose of radioactive polonium was slipped into Litvinenko's tea. He died three weeks later. Moscow declined to hand over Mr Lugovoi after the CPS announced its intention to charge him in 2007, citing a constitutional ban on extraditing Russian citizens. Mr Lugovoi and Mr Kovtun, both former KGB officers, have passionately denied any connection to the spy's death. Mr Kovtun said he hoped the Russian authorities would be equally "firm" in refusing to give him up, but expressed a willingness to co-operate with the investigation. He was consulting a lawyer over his defence, he said, and expected to receive "documents containing secret materials." "I have to sign an agreement not to divulge information," he added. The bringing of a charge against him was "connected with the increase of tension in Russia's internal political situation" Mr Kovtun added in a television interview. He did not elaborate. The 2006 murder led to a sharp downturn in Russian-British ties. The UK ejected four Russian diplomats in response to Moscow's refusal to extradite Mr Lugovoi, and the Kremlin responded in kind. Litvinenko served in the KGB in the late 1980s and then in its successor agency, the FSB (Federal Security Service). He fled to London in 2000 after being charged with abuse of office, and befriended the self-exiled Russian tycoon Boris Berezovsky, a fellow critic of then President Vladimir Putin. Litvinenko's wife and friends believe he was assassinated because of his vocal opposition to Putin. Mr Lugovoi became a minor celebrity in Russia after the murder and is currently an MP from the ultranationalist Liberal Democratic Party. The CPS refused to comment on Mr Kovtun's case.