ROME—Claudio Giacobazzi, the 65-year-old manager of the lucrative Intermarket Diamond Business, was an avid gun collector with a license to carry a concealed weapon in his native Italy. But when it came to taking his own life, it appears he chose a heavy plastic bag placed over his head, secured by a thick rubber band. A suicide note was found near the body when it was discovered in the single room he’d taken at a roadside hotel just off the highway between Parma and Modena.

It’s incredibly hard to suffocate yourself. No matter how desperate one may be to die, doctors say, the body usually reacts on its own at a certain point, trying to cling to life. Investigators, not entirely convinced that Giacobazzi managed to finish himself off, have ordered an autopsy to determine whether he had help.

However it is that Giacobazzi died, he had accrued some dangerous enemies, and was the subject of some very ugly allegations. He was under investigation by prosecutors in Milan for defrauding his clients by selling them investment diamonds worth far less than they paid, bilking them out of hundreds of thousands of dollars. And just days before he turned up dead, he had lashed out at reporters who doorstepped him at his country estate near Milan. They had wanted to ask him about the charges of fraud, and about what happened to the woman who founded Intermarket Diamond Business, and then to her husband and heir.

Giacobazzi’s is not the only demise that’s a little hard to explain in this multi-faceted story of death and diamonds.

Antinea Massetti De Rico grew up in a family from Argentina’s nobility that, like many others, had fallen on hard times in 1960s Buenos Aires. A young woman with big dreams but little hope of achieving them, she left for Europe to pursue a better life. She arrived in Switzerland in the early 1970s aiming to be a stockbroker, but all the doors in that business were closed to women.

Then, in Zurich, she met a savvy Italian money man named Michele Sindona. He was a self-made millionaire—or at least that’s the yarn he spun—with a string of banks and financial service businesses spanning nine countries, including the Franklin National Bank in Long Island, New York, and Amincor Bank right there in Zurich.

Recognizing her business acumen, Sindona hired the young Argentine to work in the stock trading section of Amincor. It was there she learned the value of diamonds not only as gems, but as investments. Diamonds didn’t devalue like Europe’s national currencies, which were often manipulated when a country’s national debt grew, and they were much easier to hide.

That last point would have been of special interest to some of Sindona’s clients, who called him “The Shark.” While Massetti De Rico may have known him as an international financier, he was in fact a highly skilled swindler and money launderer tied to three of the most powerful and opaque organizations in the world: the Sicilian Mafia, the Vatican, and what would become a particularly infamous lodge of Freemasons.

For the Mafia, he had been entrusted to hide the heroin profits funneled to him by the powerful Gambino family branch of the Sicilian Cosa Nostra in America, which he handled easily through his banks in Italy, Switzerland, and the United States, according to court records that are still used by detectives to study white collar criminal networks.

Sindona also used the close ties he had forged between his Amincor Bank in Switzerland and the Banco Ambrosiano in Rome, which was the main shareholder of the Institute for Religious Works more commonly known as the Vatican Bank. Through that alliance, Sindona became a close associate of American Bishop Paul Marcinkus. They had met through the Propaganda Due (P2) Masonic Lodge which was dissolved amid a succession of scandals in the mid 1970s. (Some conspiracy theorists even link Marcinkus to the untimely death of Pope John Paul I just 33 days after he was elected, a legend exploited by Francis Ford Coppola in the last installment of the Godfather trilogy.)

In 1974, after a stock market crash, Sindona’s American-based Franklin Bank started hemorrhaging assets. His personal relationship with President Richard Nixon had helped protect his operations, but Nixon had just resigned. Sindona was terrified of the punishment he might face for losing the mob’s heroin money and just as fearful of what might happen if he defaulted on the Vatican Bank’s assets entrusted to him.

Eventually, he did both. And his financial ruin sparked massive losses for the Vatican’s banking partner Banco Ambrosiano. Roberto Calvi, its president, known as “God’s Banker,” ended up hanging under Blackfriar’s Bridge in London, his pockets weighed down with bricks that didn’t have his fingerprints on them.

Sindona eventually was convicted of 65 counts of conspiracy, fraud, perjury, and murder, after ordering a hit on an Italian lawyer charged with liquidating his complicated assets. He died in an Italian prison of cyanide poisoning just a few days into his life sentence, either by his own hand or, more likely, by a fellow mafioso exacting revenge for the money he cost the mob.

Massetti De Rico, apparently an innocent witness to all this, realized that the only people who didn’t lose their savings in Sindona’s web of deceit were those who had invested their money in diamonds. So, in 1976 she moved to Milan and founded Intermarket Diamond Business or IDB, which sold these radiant stones to wealthy clients who needed a safe investment.

Her company was the first of its kind in Italy, marrying the precious gem trade to banking practices. These were not mere baubles for earrings, bracelets, and necklaces, vouched for by a salesperson in some jewelry store or diamond district. Massetti De Rico made sure the diamonds’ value was certified at the time of purchase, and she provided financial services to help investors.

IDB doubled its profits in the first few years. She insisted on securing a legal pedigree for the diamonds her financial institution sourced and sold, but the real key to her success was the fact that diamond investing fell through almost every fiscal loophole in every country, with no restriction on the number investors could own or on value limits of each individual gem. Not long after it launched, IDB was earning more than $200 million a year, according to the company’s profile.

The Argentinian may also have learned something else from Sindona’s demise—not to let the mob invest in her business. In 2008, she testified before an Italian anti-Mafia court that she had refused the sale of a 5 percent stake in her company by a Swiss financier who she learned was tied to the Calabrian Mafia known as the ‘Ndrangheta. It apparently was laundering drug profits for the Ferrazzo di Mesoraca and Pane-Iazzolino di Sersale clans. A few years later, she also blew the whistle on members of Italy’s Northern League party (now the League, forming the new Italian government) who allegedly were buying her gems with electoral reimbursements paid to the party, in clear defiance of campaign finance regulations.

Life for the smart and attractive Queen of Diamonds was not all work. There was also romance. In the early 1980s, she married Richard Hile, an American model from California described as “Apollo-esque,” who she met during a publicity shoot for her company. In the early years of their marriage, Hile and Massetti De Rico were trendsetters among the glitzy elite of Milan. Then, friends say, Hile started to change, either from early signs of Alzheimer’s or dementia, or from drug use, which was rampant among the Milanese fashion set in the late ’70s and early ’80s. Soon, he was mentally incapacitated and, according to accounts of those who ran in their circle, stopped speaking entirely.

The diamond business was evolving. Once totally dominated by the South African company De Beers, it began to face competition from other parts of the world. There were “blood diamonds” mined by forced labor and stolen by corrupt warlords in West Africa, and at a more industrial level, there were Russian diamonds coming onto the market just as the Soviet Union was falling apart and the Moscow kleptocracy was ascendant.

Massetti De Rico and her business managed to weather all these storms. And, still, she treated her now vacant-minded husband as an equal, going to great lengths to include him in social affairs until it proved far too difficult for her to keep up the ruse.

Eventually, misfortune befell her as well.

In 2011, not long after the case in which she testified against the ‘Ndrangheta, and after convictions were handed down, she slipped on the marble floor of a posh Milanese café after her morning cappuccino and hit her head, suffering immediate, severe brain damage which condemned her to a semi-permanent vegetative state.

Her fall was an accident, according to witnesses, although it still raises eyebrows.

The couple had no children and with Hile lacking the ability to manage their vast financial affairs, they were easily prone to exploitation.

By then, the global diamond industry was turning over around $74.3 billion a year, and no one involved in IDB’s business was ready to dissolve the company just because the founder and only heir were incapacitated.

IDB’s second in command at the time of Massetti De Rico’s fall was none other than Claudio Giacobazzi, who happened to be with her in the Milanese cafe that fateful morning. He quickly became both president of the company and administrator of Massetti De Rico’s entire estate, including acting as trustee for the two trust funds the couple had set up as the Antinea-Hile Onlus and the Hile Trust, which still owns the vast bulk of IDB diamond business.

So long as the owners of IDB were still alive, things carried on at a lucrative pace, but not everyone agreed with the way the business was being run. For one thing, Giacobazzi was not as bothered with the provenance of the precious gems IDB sold, and because of IDB’s reputation under Massetti De Rico, most clients wrongly assumed business as usual.

Ilaria Mazzei, an administrator working under Giacobazzi, started collaborating with a local prosecutor in Milan, who asked her to document various dealings and suspicious arrangements, which she started tracking around 2013, creating a thorough dossier complete with facts and figures tied to at least 10 people who were entrusted with caring for the affairs of the incapacitated couple.

In 2015, thanks to a tip, a lawyer representing Massetti De Rico’s family in Argentina along with one representing one of Hile’s three American siblings, started inquiring about the state of their loved ones and, ultimately, the value of the queen of diamond’s considerable wealth.

Around that time, Giacobazzi allegedly acted unilaterally to move both Hile, who was in no position whatsoever to argue, and the comatose Massetti De Rico, who was even less so, to the Tuscan seaside town of Lucca where their affairs were signed over to the lawyer Alberto Consani. Along with his son Francesco, he assumed complete responsibility for the wealthy couple. Court documents show that Consani even had a medical court order that stated, “The doctors advise a period of distance from Milan, preferably in a seaside place.”

Those who inquired about the once-famous couple, including many who regularly visited them in their luxurious home in Milan, were simply told they had “disappeared.”

In February of 2017, Massetti De Rico died under as yet undetermined circumstances, leaving everything she owned to her husband. Five months later, her husband died as well, having left the company to Giacobazzi, Consani and Franco Novelli, a notary whose seal was on all of the inheritance documents in place of Hile’s signature.

By then, tips from the whistle-blowing administrator and the document trail were enough to form a criminal dossier that eventually led to indictments on May 10 of nine people, including Giacobazzi, Novelli and his wife, Consani and his son, and two butlers who stand accused of stealing and distributing the couple’s physical belongings, including jewelry, letters, and photos.

Armando Simbari, the defense attorney for Consani and his son (the duo who assumed care of the diamond couple in Tuscany), says the charges are unfair. Simbari claims that Hile’s family had abandoned him, and that his client instead acted to protect him from the state, which would have taken the queen of diamond’s assets.

The court also seized more than $75 million in bank assets tied to the two trust funds.

The suspects face charges of criminal association, delinquent acts against incapacitated people, fraud, forgery, and kidnapping of a comatose and incapacitated person. As that case proceeded, it came to light that IDB and its associate banks under Giacobazzi’s leadership already had been fined more than $15 million by Italy’s antitrust authorities last October for passing off low-grade diamonds with forged certificates for top-quality gems.

Lawyers for both Hile and Massetti De Rico have chosen not to comment publicly on the case while the latest twist is being investigated, but privately sources close to both families say they are concerned that with Giacobazzi now dead the trial could be stalled indefinitely, keeping IDB’s assets frozen and leaving investors wondering if, as they had hoped and believed, their fortune in diamonds really is forever.

—with additional reporting by Christopher Dickey in Paris