MSNBC confirms that British investigators have concluded Alexander Litvinenko was murdered in Kremlin-sponsored assasination and that the Kremlin is obstructing justice in the investigation. Dateline NBC had a companion broadcast over the weekend, read the transcript here.

Although British police are apparently certain that exiled Russian dissident Alexander Litvinenko was assassinated in a plot orchestrated by elements of the Russian security service, they may never be able to bring charges against anyone because of diplomatic sensitivities and resistance from the Russian government, a “Dateline NBC” investigation has found.

The Kremlin has denied responsibility for Litvinenko’s death, which drew worldwide attention late last year as he excruciatingly wasted away from the poisonous effects of the radioactive isotope polonium 210. A spokesman for President Vladimir Putin told “Dateline” that the assassination was most likely carried out by enemies who wanted to ruin Russia’s image, and Putin himself said at a recent news conference that Litvinenko was not on the Kremlin’s radar.

But a review of the evidence and police statements, as well as “Dateline” interviews with British and Russian experts close to the case, members of Litvinenko’s family and a former senior KGB official, suggests that the police are confident they have solved the case. The question now is whether they will ever be able to do anything about it.

Paul Joyal, Russia expert, security consultant: A message has been communicated to anyone who wants to speak out against the Kremlin: “If you do, no matter who you are, where you are, we will find you and we will silence you—in the most horrible way possible”.

An athlete wastes away

Litvinenko, 43, died Nov. 23 in full view of the world, which watched as he slowly deteriorated into a bald, frail husk of the robust distance runner he had been just three weeks earlier. He was a decorated KGB counterintelligence agent before being promoted in 1997 to senior operational officer in the department investigating organized crime at the FSB, as the KGB was renamed in 1991 after the fall of the Soviet state.

But in 1998, he ran afoul of Putin, who was then head of the FSB. Along with four other FSB agents, Litvinenko appeared at a news conference to accuse the head of the organized crime directorate of ordering the assassination of Boris Berezovsky, a powerful businessman and political schemer who was an ally of President Boris Yeltsin.

Litvinenko, who tipped off Berezovsky to the plot, was fired and arrested three times. After being jailed for a month, he was released when he promised never the leave the country. Using a forged passport, he sneaked himself, his wife and their young son out of the country and sought asylum in London on Nov. 1, 2000 — six years to the day before he was poisoned.

In exile in London, Litvinenko undertook a new calling as an anti-Kremlin journalist, writing exhaustively about what he saw as the abuses of the Russian government in its fight against Chechen separatists during the 1990s.

He accused the FSB of having set off the bombs that killed more than 300 people in explosions at apartments in Russia in 1999, which the government blamed on Chechen separatists and used to justify its second war in Chechnya. Likewise, he charged, at least two of the Chechen separatists who took hostages at a theater in Moscow in October 2002, in which 162 people died, were in fact working for the FSB.

Over time, his accusations grew more extreme. He accused the FSB of having trained Ayman al-Zawahiri, the deputy leader of al-Qaida, during the late 1990s. He published an article accusing Putin of being a pedophile.

Then, last October, a crusading Russian journalist, Anna Politkovskaya, who had become internationally prominent for her exposés of the government’s activities in Chechnya, was gunned down outside her home. Litvinenko began looking into that case and accused Putin of having ordered Politkovskaya’s assassination.

That may have been the last straw — the Kremlin was already under international pressure from journalists and human rights groups highlighting the number of prominent anti-Putin journalists who have been killed during the last few years.

Zeroing in on the FSB

Investigators are reported to believe that the plot to kill Litvinenko involved two Russian businessmen, Andrei Lugovoi, a former KGB agent, and Dmitri Kovtun, a former army officer, who met with Litvinenko on Nov. 1 at the Millennium Hotel in London. Litvinenko’s teapot and cup, the hotel bar and several members of the bar’s staff were found afterward to have been contaminated with polonium 210.

Police called the killing “state-sponsored” in a document urging the Crown Prosecution Service to file conspiracy charges against Lugovoi, who, like Kovtun, denies involvement in any plot.

However, those charges are not likely to come any time soon, if ever, despite extensive evidence that appears to trace responsibility for Litvinenko’s killing directly to Moscow, “Dateline” found.

At the same time that it is dismissing the case as irrelevant, the Russian government has opened its own investigation. British authorities have resisted the development for fear that the probe would be used as diplomatic cover for Russian agents to track down political opponents inside Great Britain, but Russian investigators arrived in London last week to begin work.

In the meantime, the Russian government has barred British investigators from returning to Moscow while its inquiry proceeds, and it has insisted that any Russian citizen charged in the case must be tried in Russia. Both developments could delay British action indefinitely

On a parallel track, the investigation is being stalled by reluctance to trigger a full-scale diplomatic confrontation should British prosecutors go public with an accusation that Russia has authorized political assassinations outside its borders.

Daniel McGrory, a senior correspondent for The Times of London, has reported many of the developments in the Litvinenko investigation. He said the police were stuck between a rock and a hard place.

“While they claim, and the prime minister, Tony Blair, has claimed nothing will be allowed to get in the way of the police investigation, the reality is the police are perfectly aware of the diplomatic fallout of this story,” McGrory said.

“Let’s be frank about this: The United States needs a good relationship with Russia, and so does Europe,” said Paul M. Joyal, a friend of Litvinenko’s with deep ties as a consultant in Russia and the former Soviet states.

Noting that Russia controls a significant segment of the world gas market, Joyal said: “This is a very important country. But how can you have an important relationship with a country that could be involved in activities such as this? It’s a great dilemma.”

‘Up to the top’

As yet unclear is how much, if any, Putin himself may have known about the operation.

Joyal and Litvinenko’s widow, Marina, both told “Dateline” it was probably no coincidence that Litvinenko was poisoned only a few months after he published an article accusing Putin of pedophilia.

“There’s a section in the law that gives the authority of the Russian state the ability not only to go after and assassinate terrorists, but also to take steps against those who slander the leader of the nation,” Joyal said. “So, in a legalistic frame, some may think that they would be justified in taking certain steps if a man would slander the Russian president.”

Joyal said it was still too soon to conclude that Putin was involved in the plot, but if he was not, Joyal said, he certainly knows now who was.

“We do know this: Elements of the state were actively involved in this,” Joyal said. “I would find it hard to believe that this information, whatever it may be, has not filtered its way up to the top.”

‘Dignity and Honor’

Specifically, “Dateline’s” investigation shows that much of the evidence could lead to the former KGB. For years, there have been whispers of shadowy confederations of intensely loyal former agents in groups like Dignity and Honor, nostalgic for the old days of KGB supremacy and devoted to hunting down enemies around the world.

The use of polonium, for example — and in such a large amount — narrows the field of suspects drastically. International regulators say the isotope is produced and stored almost exclusively in Russia.

Moreover, polonium is hard to acquire, dangerous to handle and extremely expensive, said Steve Fowler, a radiation safety consultant who heads Fowler Associates, a radiation processing complex in Moore, S.C. It is highly unlikely that anyone could have acquired the amount used in Litvinenko’s assassination — which Fowler estimated at $2 million to $3 million worth — without the cooperation of some element of the Russian government.

The polonium trail “will all lead to the government institutions,” said retired Maj. Gen. Oleg Kalugin, who for many years was head of the KGB’s operations in Washington.

“It could not be obtained by private individuals,” Kalugin told “Dateline.” “The Russian government agencies release the stuff needed to poison people abroad, including Mr. Litvinenko.”

Although experts say a minuscule dose of polonium can be fatal, the killer or killers used so much — at least 10 times the lethal dose — that they left a wide trail. At least 127 people who may have crossed the paths of Litvinenko, Lugovoi or Kovtun have tested positive for exposure at about 20 sites around London, police say.

Joyal, the Russia security expert, said that was probably done on purpose.

“The substance used in his murder, it’s clear-cut,” said Joyal, former chief of security for the U.S. Senate Intelligence Committee. “It has to be a state-run or a state-managed operation. ...

“A message has been communicated to anyone who wants to speak out against the Kremlin,” he said. “If you do, no matter who you are, where you are, we will find you, and we will silence you, in the most horrible way possible.”

The hit list

A few hours before he was poisoned, Litvinenko also met with Mario Scaramella, a 36-year-old Italian lawyer who fashions himself as an international security consultant.

Scaramella had interviewed Litvinenko as part of his own investigation of alleged Cold War links between the Italian government and the KGB, and he has told reporters that he wanted to give Litvinenko information about Politkovskaya’s death.

Among the information was what Scaramella characterized as a hit list maintained by Dignity and Honor, the confederation of hard-line former agents of the KGB. One of the names in the document, a copy of which was obtained by “Dateline,” was Politkovskaya’s. Another was Scaramella’s.

For Dignity and Honor, Litvinenko would have been an especially valuable target, said Kalugin, a KGB-era rival of Putin’s who has become a critic of the Kremlin and the FSB since emigrating to the United States in 1995.

And because of Putin’s close connections to the FSB, the president “stood behind the assassination,” Kalugin charged. “I am positive about it. ... Putin belongs to that category of people who do not forgive.”

Investigators running in place

Lugovoi and Kovtun strenuously deny that they had anything to do with Litvinenko’s murder. They say they are businessmen who were simply exploring a deal with a well-connected expatriate.

The told “Dateline” that somebody posing as a barman or a member of the hotel staff must have slipped the polonium into Litvinenko’s tea. They point out that they did not flee London after Litvinenko took ill and that they contacted British authorities themselves when they learned that Litvinenko had been poisoned.

Moreover, they note, they, too, were contaminated with polonium and had to check into a Moscow hospital.

Police appear certain they have found their men, however, and are reported to have recommended conspiracy charges against Lugovoi even though they cannot establish a direct motive. The men may have been “merely following orders” without being fully aware why Litvinenko was targeted, or they may have been “under some kind of coercion, threat or bribe,” surmised McGrory, the Times reporter.

But whether or not Lugovoi or Kovtun personally slipped the polonium into Litvinenko’s cup — investigators are also seeking a third man spotted on surveillance cameras, whom they have identified only as “Vladislav” — police are apparently convinced that the assassination was hatched by the FSB or true-believer former agents loyal to Putin.

That is an assessment shared by Marina Litvinenko, who does not accuse Putin of directly ordering her husband’s assassinaton but says he allowed a culture of violent retribution to flourish.

“Everything what happened in Russia, if it’s happened, it’s Putin decide to do it,” Marina Litvinenko, who speaks broken English, told “Dateline.” “Because without him, it’s just impossible.”

It is an assessment shared by Oleg Kalugin, the onetime top spy for the KGB.

Litvinenko “was a traitor. So was I and a number of others. They have a list,” Kalugin said. “They would love to kill him.”

And it is an assessment shared by Paul Joyal, the Russia specialist. Joyal believes the Kremlin is resisting the British investigation because it is guilty and is hoping to run out the clock.

“It’ll go away in time,” he said. “Maybe not this week. Maybe not next week. But if you just hang in there and deny, at the end of the day — if there’s no one stepping forward saying, ‘I know’ — it will be forgotten.

“And there’s nothing anyone can do.”

OTHER NOTCHES ON THE KREMLIN'S HIT LIST:

Anna Politkovskaya
Politkovskaya, 48, an internationally known reporter and a leading critic of Putin, was shot to death Oct. 7, 2006, in her apartment building. She survived a poisoning after covering the 2004 siege of a school in Beslan; like Alexander Litvinenko, she fell ill after drinking tea.

Igor Domnikov
Domnikov, 41, a reporter and colleague of Anna Politkovskaya at Novaya Gazeta, died July 16, 2000, two months after he was bludgeoned in the entryway to his apartment in Moscow and left in a coma.

Yuri Schekochikhin
Schekochikhin, 53, an editor at Novaya Gazeta who was reporting on the the 1999 apartment bombings, died July 3, 2003, of an "extreme allergic syndrome." Relatives said he was poisoned, but the files were closed, and there was no investigation.

Artyom Borovik
Borovik, 39, a former "60 Minutes" producer, died in the crash of a small plane March 9, 2000. He was highly critical of President Vladimir Putin as publisher of the monthly investigative newspaper Top Secret and host of an investigative television program. Police said the plane may have been sabotaged.

Vladimir Golovlev
Gologlev, 45, co-chairman of the Liberal Russia party, was shot dead Aug. 21, 2002, near his Moscow home. "The murder of one of the five co-chairmen of Liberal Russia is undoubtedly of a political nature," fellow Liberal Russia co-Chairman Sergei Yushenkov said. Unsolved.

Sergei Yushenkov
Yushenkov, 52, co-chairman of the Liberal Russia party, was shot dead April 17, 2003, outside his Moscow apartment building. He was leading an investigation of the FSB's alleged role in apartment bombings in 1999 that were the pretext for the second war in Chechnya.

Vassily Grodnikov
Grodnikov, a reporter for Norodnaya Volya, was found dead Oct. 18, 2005, in his apartment in the Minsk suburbs, killed by a blow from a blunt object. He had been working on a draft article headlined "A booked office or several uncompromising questions for the president of the country and the agencies under his control."

Andrei Kozlov
Kozlov, 41, who crusaded against Russia's corrupt banking system as deputy chairman of the Central Bank, was shot dead Sept. 14, 2006, as he left a soccer stadium.