Poisoning of Alexander Litvinenko

Alexander Valterovich Litvinenko was an officer of the Russian Federal Security Service (FSB) and its Soviet predecessor, the Committee for State Security (KGB), until he left the service and fled the country in late 2000, defecting to the UK. In 1998, Litvinenko and several other Russian intelligence officers said they had been ordered to kill Boris Berezovsky, a Russian businessman. After that, the Russian government began to persecute Litvinenko.

Source: Wikipedia — Poisoning of Alexander Litvinenko (CC BY-SA 4.0)