Any Russian citizen suspected in the poisoning of former Russian spy Alexander Litvinenko will be tried in Russia, not Britain, Russian Prosecutor-General Yuri Chaika said on Tuesday(December 5). He also said Russian prosecutors will question Litvinenko associate Andrei Lugovoy as part of co-operating with British detectives investigating the case in Moscow. Lugovoy met Litvinenko on November 1, the day he fell ill. Meanwhile Yegor Gaidar, architect of Russia's market reforms, was released from a Moscow hospital late on Monday (December 4) where he was taken after collapsing at a conference in Ireland. His spokesman Valery Natarov on told Reuters TV that the doctor's diagnosis has shown Gaidar's ailment was caused by unnatural causes. "The doctors are very flexible in their terms and they do not use the word of poison. They say intoxication of the body, caused by some unnatural products. Due to the medical ethics they can not use the word poison, while not verifying what has caused the contamination," Naratov said. He said Gaidar would continue treatment at home. Gaidar, 50, a former acting prime minister and now an influential academic, was taken to hospital last month shortly after the death in London of former KGB agent Alexander Litvinenko from radiation poisoning. Litvinenko accused Russian President Vladimir Putin of killing him but the Kremlin has denied any link to the death. Moscow residents on Tuesday reacted with scepticism to efforts by British investigators from Scotland Yard to solve the murder of Litvinenko, who defected to the United Kingdom in 2000. A small group of British police officers arrived at the Domodedovo airport on Monday evening to begin widening their probe into Litvinenko's death, who succumbed in a London hospital on November 23 to a lethal dose of radioactive Polonium 210. "I can't comment on (the investigation); it is a very confusing question,'' said Grigori, a Moscow resident. ``I think that it's aimed toward discrediting Russia.'' Answering reporters' questions on the presence of British police in Moscow, Chaika said: "They (British detectives) do not have the right to lead interrogation only we can do that and they can only be present," Chaika said it was not possible that any suspects be sent to Britain. No one has to date been charged with offences related to Litvinenko's death. The radioactive polonium 210 used to poison former Litvinenko in London could not have originated in Russia, Prosecutor-General Yuri Chaika said on Tuesday. At the same news conference, the prosecutor also said Russian investigators have solved the murder of deputy central bank chief Andrei Kozlov who was shot dead in Moscow. Kozlov, who as Russia's chief banking supervisor led a crusade to clean up the murky financial sector, was shot in a gangland-style "hit" on September 13 and died the following day. Officials later said three people had been arrested and had confessed to having been hired by an unknown person to carry out the contract killing. However, investigators have so far been unable to say who was behind the murder which cast a shadow over one of the main achievements of President Vladimir Putin's presidency -- the revival of law and order. "In the course of the investigation a number of people, directly linked to the murder, have been arrested so the crime is considered solved," Prosecutor-General Yuri Chaika said. Chaika made no further comments and it was not clear whether investigators were still tracking the organisers of Kozlov's killing. Meanwhile in London Mario Scaramella, an Italian contact of Litvinenko who also suffered poisoning from polonium 210 was due to be released from University College Hospital on Tuesday.