After leaving the FSB , he blamed the service for orchestrating a series of apartment bombings in Russia in 1999 that left hundreds dead and led to Russia 's invasion of Chechnya later that year . Alexander Litvinenko died in 2006 after being poisoned by radioactive material . A public inquiry into the former KGB officer 's suspicious death began in London . Russian President Vladimir Putin was accused by the ex - spy of being behind it .
Alexander Litvinenko died in 2006 after being poisoned by radioactive material . A public inquiry into the former KGB officer 's suspicious death began in London . Russian President Vladimir Putin was accused by the ex - spy of being behind it .