Alexander Valterovich Litvinenko (Алекса́ндр Ва́льтерович Литвине́нко) (30 August 1962 – 23 November 2006) was a lieutenant-colonel in the Federal Security Service of the Russian Federation, and later a Russian dissident and writer. Litvinenko became a KGB officer in 1986, and two years later, was moved into the Military Counter Intelligence.

He was promoted to the Central Staff, and specialised in counter-terrorism and infiltration of organised crime. Six years later, he was promoted to senior operational officer and deputy head of the Seventh Section of the FSB. In November 1998, Litvinenko publicly accused his superiors of ordering the assassination of Russian billionaire Boris Berezovsky. He was arrested by Russian authorities and then released; he later fled to the United Kingdom.

Litvinenko published two books, "Blowing up Russia: Terror from within" and "Lubyanka Criminal Group" in which he described Vladimir Putin's rise to power as a coup d'état organised by the FSB. He stated a key element of FSB's strategy was to frighten Russians by bombing apartment buildings in Moscow and other Russian cities. He alleged the bombings were organised by FSB and blamed on Chechen terrorists to legitimise reprisals using military force in Chechnya. This version of events has been supported by Russian lawmaker Sergei Yushenkov, historian Felshtinsky, and political scientist Pribylovsky. It has been also described by Johns Hopkins University and Hoover Institute scholar David Satter, in his book and statements in US congress David Satter. Darkness at Dawn: The Rise of the Russian Criminal State. Yale University Press. 2003. ISBN 0-300-09892-8.

In his articles and public presentations he also stated that Russian secret services have arranged Moscow theater hostage crisis through their Chechen agent provocateur, that they organized 1999 Armenian parliament shooting, and that terrorist Ayman al-Zawahiri was under their control when he visited Russia in 1997. He had warned Anna Politkovskaya that she might be killed in Russia on the order from Putin, and that FSB agents are prepared to assassinate him, Boris Berezovsky and Akhmed Zakayev.

On 1 November 2006, Litvinenko suddenly fell ill and was hospitalised. He died three weeks later, becoming a rare victim of lethal polonium-210 radiation poisoning under highly suspicious circumstances. The fact that Litvinenko's revelations about alleged FSB misdeeds were followed two years later by his poisoning led to public accusations that the Russian government was behind his death, resulting in worldwide media coverage. A British police investigation resulted in several suspects for the murder, but in May 2007, the British Director of Public Prosecutions, Ken Macdonald, announced that his government would seek to extradite Andrei Lugovoi, the chief suspect of the case, from Russia. On 28 May 2007, the British Foreign Office officially submitted a request to the Government of Russia for the extradition of Lugovoi to face criminal charges in the UK with On 5 July 2007, Russia officially declined to extradite Lugovoi, citing that extradition of citizens is not allowed under the Russian constitution. Russia has said that they could take on the case themselves if Britain provided evidence against Lugovoi but Britain has not handed over any evidence. The head of the investigating committee at the General Prosecutor's Office said Russia has not yet received any evidence from Britain on Lugovoi. "We have not received any evidence from London of Lugovoi's guilt, and those documents we have are full of blank spaces and contradictions.

According to medical professionals, "Litvinenko’s murder represents an ominous landmark: the beginning of an era of nuclear terrorism." , although Litvinenko was not the first victim of a radiological attack. blank">Radiological Terrorism: “Soft Killers” by Morten Bremer Mærli, _Bellona Foundation .

The involvement of the Russian government in the apartment bombings has been sometimes described in media as a "conspiracy theory" However, the assassination of Litvinenko, allegedly by Russian agents, was "the most compelling proof" of all his theories according to his biography book :