PORTICELLO, Sicily (AP) -- Specialist cave divers working in 12-minute underwater shifts were searching Tuesday for six missing passengers and crew, including British tech tycoon Mike Lynch, believed to be in the submerged wreck of a luxury yacht that was slammed by a powerful storm and swiftly sank off Sicily.

The sleek yacht, named the Bayesian, was carrying a crew of 10 people and 12 passengers when it suddenly sank near the Mediterranean island that is part of Italy at about 4 a.m. on Monday. One body has been recovered and 15 people survived.

Fire rescue officials have said the six believed to remain in the sailboat's hull will be considered missing until they are located in the wreckage.

Here's what we know so far about the sinking and those who were on board.

Italian civil protection officials believe a sudden and fierce storm that battered the coast of Sicily in the early hours of Monday whipped up a waterspout in the exact spot where the 56-meter (184-foot) British-flagged Bayesian was moored.

Karsten Borner, the captain of another yacht moored nearby, said he saw the Bayesian during the storm but when the wild weather passed it was gone and he saw only a red flare lighting the night sky, ANSA and the Giornale di Sicilia newspaper reported.

Borner and one of his crew boarded their tender and found a lifeboat carrying 15 people, some of them injured. They took them aboard their yacht and alerted the coast guard.

Rescue authorities said the wreck was resting at a depth of 50 meters (163 feet) about a half mile offshore of the picturesque fishing village of Porticello.

Among the missing is 59-year-old tech tycoon Mike Lynch, sometimes described as the British Bill Gates. Lynch was acquitted in June of all charges in a U.S. fraud trial linked to the $11 billion sale of his software company Autonomy to Hewlett-Packard in 2011.

Lynch still faced a potentially huge bill stemming from a civil case in London that HP mostly won during 2022. Damages haven't been determined in that case, but HP is seeking $4 billion. Lynch made more than $800 million from the Autonomy sale.

A Cambridge-educated mathematician, Lynch made his name running Autonomy, which made a search engine that could pore through emails and other internal business documents to help companies find vital information more quickly.

Lynch's 18-year-old daughter Hannah was reportedly among the missing. His wife, Angela Bacares, and 14 other people survived.

Among others still missing Tuesday, according to the civil protection agency, were one of Lynch's U.S. lawyers, Christopher Morvillo of Clifford Chance, and Morvillo's wife. Morvillo was regarded as an elite defense lawyer and was also a federal prosecutor in New York after 9/11.

Also missing was Jonathan Bloomer, the chairman of Morgan Stanley International, and his wife, Judy. He is the former head of the Autonomy audit committee and testified for the defense at Lynch's trial.

Bloomer was also chair of the Hiscox Group, an insurer that does business on the Lloyd's of London market.

"We are deeply shocked and saddened by this tragic event," Hiscox CEO Aki Hussain said in a statement. "Our thoughts are with all those affected, in particular our chair, Jonathan Bloomer, and his wife Judy, who are among the missing, and with their family as they await further news from this terrible situation."

Among the survivors was Charlotte Golunski, who said she momentarily lost hold of her 1-year-old daughter Sofia in the water, but then managed to grab her and hold her up over the waves until a lifeboat inflated and they were both pulled to safety, Italian news agency ANSA reported. The father, identified by ANSA as James Emslie, also survived.

The Dutch foreign ministry said a Dutch man survived. The ministry, citing privacy, did not release his identity.

One body was recovered on Monday, identified as the on-board chef.

The Bayesian was a luxury yacht built in 2008 by the Italian firm Perini Nav. It was known for its single 75-meter (246-feet) aluminum mast -- one of the world's tallest. Online charter sites listed it for rent for up to 195,000 euros (about $215,000) a week.

Its registered owner is listed as Revtom Ltd., based on the Isle of Man, according to online maritime database Equasis. Lynch's wife is listed as Revtom's sole owner, according to corporate registration documents from the Isle of Man.

The yacht's name is an apparent reference to "Bayesian inference," one of the two main approaches to statistical machine learning and the one that was used by Autonomy.

Waterspouts are tornadoes that form over water and can happen when a storm moves across warm water.

According to the U.S. National Ocean Service, there are two types of waterspouts -- fair-weather and tornadic.

Tornadic waterspouts "have the same characteristics as a land tornado. They are associated with severe thunderstorms, and are often accompanied by high winds and seas, large hail, and frequent dangerous lightning," the service says on its website.

While scientists haven't attributed the specific event to climate change, average monthly surface temperatures have been at record highs for months. Hotter air can hold more moisture, making heavier storms more likely.

Sicily has been baking under intense heat this summer, and the United Nations' panel of climate change experts notes the Mediterranean is particularly vulnerable to climate change, with warming rates roughly 20% higher than the global average.

As the search for the missing continues, authorities already have begun trying to piece together exactly what happened.

Prosecutors from the Sicilian town of Termini Imerese have opened an investigation, as is normal in such events even when no suspects are identified. To date they have not commented publicly.

The British Marine Accident Investigation Branch said four of its inspectors were being deployed to Palermo.

Corder reported from The Hague, Netherlands.