Alexander Valterovich Litvinenko used to be an intelligence officer for the Russians. He specialized in counter-terrorism and infiltration of organized crime. That means he knew sensitive things about what criminals in Russia were doing. He also knew about terrorism and about how much the Russian Government was or wasn’t doing to prevent terrorism in the Western world. What did he know? What could he have revealed? It seems he knew that bad men higher up in his organization had arranged for Russian the murder of a very rich and influential Russian, Boris Berezovsky. There may have also been threats to Litvinenko.
Then in 1998, Litvinenko called a press conference, claiming that a year earlier he had been instructed to kill Berezovsky by then deputy head of the Russian security council. Flanked by other members of his FSB unit, one in a black balaclava, Litvinenko said his superiors had threatened him with violence when he refused their order to "kill the Jew who'd robbed half the country". 
Arrests and trials
Litvineko was arrested for exceeding his authority not for saying anything untrue and was acquitted after enduring the harsh conditions of a Russian remand centre for nine months. . He was twice tried and acquitted twice for revealing what the Russians didn't want people to know. Then he was charged a third time. Russia doesn’t respect the rule against Double-Jeopardy.
Litvineko in Britain
Litvineko fled to Britain where he wrote two books, "Blowing up Russia: Terror from within" and "Lubyanka Criminal Group". In these books he said that Russian agents had done terrorist acts which included blowing up whole blocks of flats in order to get Vladimir Putin into power and of arranging to get journalist Anna Politkovskaya murdered.
Murder of Litvinenko
Litvinenko was a very brave man as he knew what these murderers are capable of doing and must have known that he was risking his life. We honour his sacrifice. Andrey Lugovoy is suspected of poisoning Alexander Litvinenko. Lugovoy allegedly poisoned him in the U.K. in 2006 . On his death bed Litvinenko accused many important Russians of doing horrendous things. He was only 43 years old.  The public will never find out if he knew even more. Obviously one of the best things Russia could have done to discredit him would be to let him live. The poison was radioactive and cost $100 million but Russia refused to extradite the guy suspected of it so the British got very angry at the Russians. To make things worse Lugovoy became a Russian parliament , which is showing how little the Russians care, when you really think about it. Naturally the United Kingdom government expects people to be safe from foreign attack when on British soil. For some time after the poisoning relations between the UK and Russia were strained.
An official Inquest was started in 2013, that's surprisingly late as Litvinenko died in 2006. The coroner in charge of the inquest said he couldn't hear all the relevant evidence due to national security and Litvinenko's widow wants a public inquiry where all the evidence could be heard, if necessary some could be heard in secret. Many people suspect some type of deal between the UK government and the Russians to hush up inconvenient truths.  In 2014 an official enquiry was announced. 
- ↑ Alexander Litvinenko, Security agent sucked into a world of Russian power games and oligarchs
- ↑ Obituary: Alexander Litvinenko: BBC News
- ↑ ABC News Exclusive: Murder in a Teapot Andrei Lugovoi: Russian politician accused of murdering Alexander Litvinenko with polonium
- ↑ Why I believe Putin wanted me dead... By ALEXANDER LITVINENKO
- ↑ Russia suspect running to be MP
- ↑ Litvinenko's widow seeks public inquiry into death
- ↑ Alexander Litvinenko death: Home secretary announces inquiry
- ↑ Litvinenko inquiry to rule on former Russian spy's killing
- ↑ President Putin 'probably' approved Litvinenko murder