If Mr. Vesco indeed eluded the American authorities until his final day, it was the fitting end to his nearly four decades on the run. He was wanted for, among other things, bilking some $200 million from credulous investors in the 1970s, making an illegal contribution to Richard M. Nixon’s 1972 presidential campaign and trying to arrange a deal during the Carter administration to let Libya buy American planes in exchange for bribes to United States officials.

Mr. Vesco last made the news a decade ago when he was sentenced to prison in Cuba, where he had taken sanctuary, for a financial scheme. He emerged in recent years and lived a quiet life in Havana until he contracted lung cancer. After about a week in a hospital, friends say, he died and was buried in an unmarked grave.

Given the controversial nature of the man, none of his friends dared be identified for fear of running afoul of the Cuban authorities. While word of Mr. Vesco’s death could be the final ruse of a 72-year-old modern-day buccaneer who had every reason to drop off the radar, it would have to be an elaborate one.

Records at Colón Cemetery in Havana indicate that a Robert Vesco was buried there on Nov. 24, and photographs and videos viewed by The New York Times show a man resembling him in a casket with his longtime Cuban companion looking over him.

Other photos show him coughing and clearly in pain in a hospital bed on what a friend said was the day before he died. There are also photos of a small group of people attending his burial.

His last days, a friend said, were in marked contrast to his ebullient pre-prison phase, when he partied lavishly, chain smoked and talked big.

Some of those who knew Mr. Vesco said it would not surprise them if he had orchestrated a fake death, to slip away one more time. “He could have died,” said Arthur Herzog, an author who interviewed Mr. Vesco in Cuba for a biography. “But Bob has used disguises in the past.”

On top of that, Mr. Herzog said, an intermediary who lives on the island had left the impression that he was in contact with Mr. Vesco in Cuba within the last month.

After a criminal odyssey that began on Wall Street, Mr. Vesco fled the United States in 1971, along the way repeatedly demonstrating the power of money to overcome any ideology.

Robert L. Vesco in 1974. He fled the United States in 1971 to avoid legal problems, and after a long odyssey avoiding American justice, friends say he died in November from lung cancer.  CreditAssociated Press

Robert L. Vesco in 1974. He fled the United States in 1971 to avoid legal problems, and after a long odyssey avoiding American justice, friends say he died in November from lung cancer. CreditAssociated Press

His associates and protectors included democratically elected presidents in Costa Rica, the left-wing Sandinistas in Nicaragua, the cocaine barons of Colombia, the terrorism-tainted government in Libya, and, finally, the Communist government of Fidel Castro.

Whereas the American government considered Mr. Vesco to be an American fugitive, he had apparently somehow gained Italian citizenship. A friend provided a copy of an Italian passport issued in 2006 that bore Mr. Vesco’s name and photograph.

The friend said representatives from the Italian Embassy had visited Mr. Vesco while he was in jail and had assisted with his funeral arrangements. An Italian Embassy official did not return calls seeking comment.

Having lived comfortably in Havana for more than a dozen years, Mr. Vesco was convicted and jailed there for fraud in 1996 after reportedly double-crossing Fidel Castro’s relatives in a bogus wonder-drug deal.

How much truth there was to the allegation was impossible to know for certain because accusations against the shadowy financier have always seemed to mix rumor and fact.

At the height of his notoriety in the 1970s, Mr. Vesco looked like a tough guy out of Hollywood central casting — tall, craggy-faced, with a mustache, long sideburns and sunglasses. He liked to burnish his image as an unpredictable rogue driven as much by perverse pride as by crass profit.

He also delighted in thumbing his nose at Cuban agents who were on his trail. They responded by suggesting that Mr. Vesco was the mastermind behind every sort of money-laundering, narcotics and smuggling plot in the Caribbean.

“With even a fraction of what he was supposed to have stolen he could have disappeared,” wrote Mr. Herzog, in his 1987 biography, “Vesco: From Wall Street to Castro’s Cuba, The Rise, Fall and Exile of the King of White Collar Crime.”

Instead, Mr. Vesco seemed to have a compulsion to call attention to himself from his places of exile. A self-made man, he seemed hardly able to help it.

A high school dropout from Detroit, he lied about his age to get a job on an automobile assembly line. At 21, he moved to New Jersey to work for a struggling manufacturer of machine tools.

He took over the company when it went bankrupt, rebuilt it and renamed it the International Controls Corporation. By the age of 30, Mr. Vesco was a millionaire.

He later turned his sights on a Switzerland-based mutual fund company, Investment Overseas Services (I.O.S.). When that, too, ran into trouble, Mr. Vesco offered to rescue the company and was embraced as a white knight by investors terrified of losing their savings.

He bought I.O.S. in 1970 for less than $5 million, gaining control of an estimated $400 million in funds. The accounting at the company had been so chaotic that Mr. Vesco, by adding a few subterfuges of his own, was able to plunder its holdings at will.

After numerous complaints, the United States Securities and Exchange Commission carried out an investigation. In 1972, the commission charged Mr. Vesco and others in a civil suit with stealing more than $224 million.

But Mr. Vesco had already fled, first to the Bahamas and then to Costa Rica. There, he established a close friendship with President José Figueres, plowing some $11 million into his adopted country.

“I wish more Vescos would come to Costa Rica — we need them,” said Mr. Figueres on television in response to criticism that he was harboring a criminal.

Mr. Vesco also befriended Donald A. Nixon Jr., a nephew of President Richard M. Nixon, and gave $200,000 to the Nixon campaign, apparently hoping the president would help quash the investigation against him.

It was to no avail. But to the frustration of the F.B.I. Mr. Vesco remained tantalizingly out of reach in Costa Rica, where he passed himself off as a progressive dairy and cattle rancher, and an investor in high-tech projects.

Eventually, one of his high-tech brainstorms — a factory to make machine guns, which included President Figueres’s son as a partner — became his undoing.

A public and political outcry ensued, and by 1978 he was forced to leave for the Bahamas, the beginning of years of hopscotching that included stops in Antigua and Nicaragua, before Cuba finally accepted him for “humanitarian” reasons.

“We don’t care what he did in the United States,” Fidel Castro said. “We’re not interested in the money he has.”

In Cuba, Mr. Vesco grew a beard, donned a white guayabera shirt and passed himself off as a Canadian citizen named Tom Adams. He and his family lived in a suburban Havana house that was modest by United States standards but lavish for Cubans. Within a few years, allegations began to circulate about Mr. Vesco’s involvement in narcotics trafficking, and he was named as a co-conspirator in the trial in Florida of Carlos Lehder Rivas, a reputed leader of Colombia’s biggest drug cartel.

Mr. Vesco eventually ran afoul of the Castro government with a scheme to produce a wonder drug that supposedly cured cancer, AIDS, arthritis and even the common cold. He was accused of defrauding a state-run biotechnology laboratory run by Fidel Castro’s nephew, Antonio Fraga Castro, and sentenced to 13 years. After serving most of his time in a private cell in a large prison in eastern Cuba, Mr. Vesco was quietly released in 2005 and lived so simply in recent years in Havana that a friend said he did not know what had happened to his fortune.