The Kremlin mounted a concerted campaign yesterday to point the finger of suspicion at the billionaire businessman Boris Berezovsky over the death of his friend, Alexander Litvinenko, after traces of radioactive polonium-210 were found at the London offices of the exiled Russian oligarch. Senior figures in the Russian establishment lined up to implicate Mr Berezovsky, who employed and funded the former KGB spy. The billionaire, who has been granted asylum in Britain, last night issued a statement mourning Mr Litvinenko’s death and saying that he had “complete faith” that Scotland Yard would conduct a “thorough and professional investigation”. Detectives are understood to want to question Mr Berezovsky in further detail about the events of November 1, the day that Mr Litvinenko, fell ill. Mr Berezovsky has declined to explain publicly why Mr Litvinenko, who was recently given British citizenship, visited his headquarters in Mayfair that day. The billionaire has accused President Putin’s regime of being behind the murder.