A British judge concluded Jan. 21 that Russia was responsible for the death of former Russian agent Alexander Litvinenko, who was given tea with a fatal dose of polonium-210. (Deirdra O'Regan/The Washington Post)

Gaunt and frail, his organs succumbing to the cruelly destructive power of radioactive poisoning, Alexander Litvinenko lay in a London hospital bed in November 2006 and identified the man responsible for his impending demise: Vladimir Putin.

Nearly a decade later, an exhaustive inquiry by a British judge concluded on Thursday that the dying former KGB operative was probably right. For the first time, the Russian president was officially implicated in a murder that seemed plucked from the pages of a Cold War spy novel but actually played out in the bar of a posh hotel in 21st-century London.

The victim: an outspoken Kremlin critic who had defected to Britain, joined the payroll of British intelligence and accused Putin of vices­ including corruption and pedophilia. The killers: a pair of assassins who, the report found, were almost certainly acting on orders from the Russian spy service, the FSB, and who left a trail of radioactive evidence strewn across London. The weapons of choice: one teacup and one massive dose of a rare nuclear isotope, polonium.

The conclusions instantly set off a furious diplomatic row, with British and Russian officials accusing each other of treachery and deceit. British Prime Minister David Cameron called the findings of “state-sponsored” murder in his capital city “absolutely appalling.” A Kremlin spokesman, without apparent irony, said the report would “further poison the atmosphere.”

But there was a limit to how much damage the report could do to relations that are already badly frayed. The inquiry’s findings come at a highly sensitive time, as the West seeks Russian cooperation in ending the Syrian war. The British government’s response to the report reflected that delicate dynamic, with officials lashing out verbally but backing away from the sort of retaliation that could truly bite in Moscow. Cameron acknowledged as much, saying that Britain needed to engage with Russia on Syria but would do so “with clear eyes and a very cold heart.”

Britain immediately summoned the Russian ambassador to express “profound displeasure” at what Home Secretary Theresa May called Moscow’s “blatant and unacceptable breach of the most fundamental tenets of international law.”

But speaking from the floor of the House of Commons, May beat back suggestions from opposition lawmakers that the government go further. She argued that Britain had already retaliated against Moscow in 2007 when preliminary inquiries into the killing suggested the hand of the Russian state.

“It is in no sense business as usual” between Britain and Russia, she said, adding that Cameron would discuss the matter with Putin “at the next available opportunity.”

That cautious stance is likely to disappoint Litvinenko’s wife, who called Thursday for Britain to expel Russian intelligence officials and enact new sanctions in response to the killing of her husband. Speaking before the government’s response became public, Marina Litvinenko said her husband’s dying belief had been vindicated.

“I am, of course, very pleased that the words my husband spoke on his deathbed — when he accused Mr. Putin of his murder — have been proved true,” she told reporters outside the Royal Courts of Justice in central London.

But it is highly unlikely that his killers will face justice any time soon for an assassination that a British parliamentary committee has described as “a miniature nuclear attack on the streets of London.”

British officials on Thursday reiterated requests for Russia to extradite the two alleged killers, Andrei Lugovoi and Dimitry Kovtun. Yet even with the new findings, Russia does not extradite its citizens, and Lugovoi has been rewarded in the years since the killing with a seat in parliament.

Lugovoi, a former KGB officer, on Thursday called the allegations against him “absurd.”

“These are lies, total lies, nonsense,” he told the Ekho Moskvy radio station.

Kovtun, now a businessman, described the charges as based on “falsified and fabricated evidence,” the Interfax news agency reported.

Britain announced Thursday that it had seized the assets of the two men, although that was believed to be a largely symbolic gesture. Ben Emmerson, the attorney for Litvinenko’s wife, acknowledged that the two would not stand trial until “the final fall of Vladimir Putin.”

The inquiry into Litvinenko’s death was led by retired High Court judge Robert Owen and was set up at the direction of the British government. The final report, the product of more than three years of work and set out over 328 pages, suggests that Putin had a personal motive for wanting Litvinenko dead because the defector had become such a fierce critic.

Although the inquiry stops short of conclusively blaming Putin — noting the opaque nature of Kremlin politics — it finds that there is “strong circumstantial evidence that the Russian State was responsible for Mr. Litvinenko’s death.” And citing the high-stakes nature of an operation to assassinate a former KGB officer on British soil, it finds that the operation would probably not have gone ahead without Putin’s direct approval.

“The FSB operation to kill Mr. Litvinenko was probably approved by Mr. [Nikolai] Patrushev [then head of the FSB] and also by President Putin,” the report concludes.

In Moscow, Putin spokesman Dmitry Peskov said that “such quasi-investigations, as we have today, can only further poison the atmosphere of our relations.”

Having worked in counter­intelligence for the KGB and its successor, the FSB, Litvinenko was fired in 1998 after holding a news conference in which he was sharply critical of the agency and, by implication, its then-director: Putin.

He defected to Britain two years later and spent years on the payroll of its main foreign intelligence agency, MI6. Litvinenko also assisted Spanish intelligence agencies with their investigations into Russian crime networks.

In addition to his covert work, Litvinenko was a prolific writer, publishing books and articles that were unsparing in their criticism of Russia’s security services generally and of Putin in particular. One article even accused the Russian president of pedophilia.

Litvinenko had become a British citizen just weeks before his death, a move that he had told friends would protect him from the reach of his jilted former Russian comrades. “Now they will not be able to touch me,” he told one, according to Thursday's report.

But in fact, Litvinenko remained very much in the sights of Russia’s security services. Troops even used a picture of his face for target practice, the report found.

Lugovoi and Kovtun have long been suspected of carrying out Litvinenko’s killing. But Thursday’s report lays out a comprehensive case linking them to his death. According to the report, the two men lured Litvinenko to the Pine Bar at the Millennium Hotel in Mayfair on Nov. 1, 2006, ostensibly to discuss a business deal, and served him a cup of cold green tea.

Traces of polonium 210 were later found in many of the places the alleged killers had visited: the bar’s bathroom, their hotel rooms, a boardroom where they conducted an earlier meeting, a soccer stadium where they watched a game and the plane that ferried them back to Russia. But the highest concentrations were discovered at the table where the three men were sitting, and in and around the teapot.

The polonium, the inquiry finds, was manufactured in a nuclear reactor, suggesting the role of a government rather than criminal networks.

The report conclusively rules out suggestions that Litvinenko poisoned himself, or that he was poisoned by others, as Russian officials have suggested.

“The scientific evidence,” Owen, the judge, said at a Thursday new conference, “demonstrates conclusively that Alexander Litvinenko was poisoned by Andrei Lugovoi and Dimitry Kovtun.”

But Owen said the two killers had no “personal reason” to kill Litvinenko. “All the evidence points in one direction, namely that when they killed Mr. Litvinenko, they were acting on behalf of someone else.”

Litvinenko became seriously ill later on the night of Nov. 1, 2006, the sixth anniversary of his arrival in Britain. He died at a London hospital 22 days later.

Birnbaum reported from Moscow. Karla Adam in London contributed to this report.

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