Moscow is pressing the United States hard to repatriate arms dealer Viktor Bout, who was convicted by a New York court Nov. 2 on four counts of terrorism and conspiring to kill Americans.

Bout, 44, is to be sentenced Feb. 8 and faces a possible life-in-prison term.

The big question is why is Russia making such a fuss about a man who helped fuel some of the developing world's bloodiest conflicts over the last two decades? What is it that has led Moscow to vow to secure his return to Russia and accuse the United States of holding him in "unjustifiably cruel conditions?"

One theory is that the Russians fear he could implicate their intelligence services in his global arms business in return for a lenient sentence.

It's highly unusual for the Russians to make such a fuss over an individual such as Bout, branded in the British Parliament years ago as "the world's leading merchant of death."

This has only fueled suspicions that Moscow has something to hide in Bout's murky activities fueling wars in Africa, the Middle East, Asia and Latin America, an industry valued at $2 billion-$10 billion a year, depending on how many conflicts are raging at any given time.

A former intelligence officer in the Soviet air force, Bout had long been linked by U.S. officials to Russia's intelligence apparatus and its arms industry, which, since the collapse of the Soviet Union and its vast military two decades ago, has survived by selling off a huge surplus of armaments.

The detailed documentation presented by U.S. attorneys in Bout's three-week trial in New York, including wiretap transcripts, provided startling new insights into the murky workings of the global arms trade.

"We've seen some useful snapshots of the way he operated," said Alex Vines, a former U.N. arms investigator who's now a research director at the Royal Institute for International Affairs, a prestigious London think tank.

"Certainly the gray areas of his involvement with the Russian government and arms industry are becoming clearer."

Many arms dealers have long operated with the tacit cooperation of the major intelligence services, among them the CIA and Britain's Secret Intelligence Service.

These agencies found the arms dealers useful in providing weapons to armies or guerrilla groups their governments were clandestinely backing.

Bout ran his own fleet of transport aircraft, mostly flown by ex-Soviet air force pilots, but given the vast quantities of East European weapons he dealt in he clearly had access to stockpiles in Russia and the former Soviet satellites.

Bout and others were invariably allied with dictators like Charles Taylor of Liberia, currently on trial by the International Criminal Court in The Hague for war crimes during the 1991-2002 civil war in Sierra Leone.

Bout was arrested March 6, 2008, in Bangkok by undercover agents of the U.S. Drug Enforcement Administration in a joint sting operation with Thai authorities.

The DEA agents were posing as leaders of the Revolutionary Armed Forces of Colombia, a violent Marxist group involved in the narcotics trade, who said they were seeking surface-to-air missiles and other weapons in a $15 million deal.

Bout was extradited to New York Nov. 16, 2010, after an epic two-year legal battle in which Moscow went to great lengths, diplomatic and non-diplomatic, to prevent Bout ending up in a U.S. courtroom.

The intensity of the U.S. effort to have Bout extradited stateside alarmed Moscow.

U.S. diplomatic cables sent from the Bangkok Embassy during that period state that the Russians bribed Thai officials to obstruct extradition and plotted to have two DEA agents arrested in Bangkok on trumped-up charges.

The Ukrainian-born Bout was widely believed to have strong links to the GRU, Russia's military intelligence, which unlike the KGB wasn't dismantled after the fall of communism and continues to operate globally.

In the 1980s, when Bout was operating in Soviet-backed Mozambique in East Africa, he served under KGB chief Igor Sechin, now Russia's deputy prime minister and arguably one of the most powerful figures in the Kremlin today.

"Moscow fears he might reveal his connections with intelligence and organized crime networks that reach high levels in the Russian government, a concern doubtless shared by other countries he dealt with," says the U.S global security consultancy Stratfor.