Original: Alexander Valterovich Litvinenko (30 August 1962 – 23 November 2006) was an officer who served in the Soviet KGB and its Russian successor, the Federal Security Service (FSB).
Simplified: Alexander Valterovich Litvinenko (December 4, 1962 or August 30, 1962 – November 23, 2006) was a lieutenant-colonel in the Russian Security Service and later a Russian dissident and writer.