PORTICELLO, Sicily (AP) — Police divers resumed searching Tuesday for six people believed trapped in the hull of a superyacht that sank in deep seas off Sicily, including a British tech magnate who was celebrating his recent acquittal on fraud charges with the people who had defended him at trial.

The resting place of their sailboat is some 50 meters (164 feet) underwater off Porticello — a depth that requires special precautions: Rescue crews said they were working in 12-minute shifts, a measure that slowed down their efforts to reach the cramped inside of the wreck.

The Bayesian, a 56-meter (184-foot) British-flagged yacht, was moored about a kilometer (a half-mile) offshore when a storm rolled in before 4 a.m. Monday. Civil protection officials said they believed the ship was struck by a tornado over the water, known as a waterspout.

Fifteen of the 22 people aboard survived, including a mother who reported holding her 1-year-old baby over the waves to save her. One body has been recovered, identified by officials as the on-board chef.

Fire rescue officials have said the other six on board will be considered missing until they are located in the wreckage. They include the tycoon Mike Lynch, who was once hailed as Britain's king of technology and was cleared in June of fraud and conspiracy charges in a U.S. federal trial related to Hewlett Packard's $11 billion takeover of his company, Autonomy Corp.

Also unaccounted for are Christopher Morvillo, one of Lynch's lawyers, and Jonathan Bloomer, a chairman at Morgan Stanley International and the former head of the Autonomy audit committee who testified in Lynch's defense.

Karsten Borner, the captain of the Sir Robert Baden Powell, which rescued the survivors who managed to get into a lifeboat, said he was close enough to be able to see the Bayesian as the storm came in.

"A moment later, she was gone," he said. "They said they went flat on the water and were sunk in two minutes," Borner added, quoting the survivors.

The rotating search teams, each made up of two specialized cave divers, worked Tuesday to open up access points to get inside the wreck, which lies at a depth far beyond what most recreational divers are certified to reach.

The divers have not yet been able to access the below-deck cabins because they were blocked by furniture that had shifted during the violent storm. Rescue crews said they assume the missing six are in those cabins because the storm struck when most would be sleeping, but the teams haven't verified their presence there through portholes.

Luca Cari, a spokesman for the rescue teams, said the search was proceeding much more slowly than another big shipwreck in Italy, the 2012 Costa Concordia cruise ship that flipped on its side off Tuscany's coast, because of the depth of the wreck and the space divers have to maneuver.

"That was much simpler. Here everything is more tight," he said.

The outing was intended at least in part as a celebration of Lynch's acquittal and a "looking forward to what was coming next," said Reid Weingarten, a Washington attorney and a member of Lynch's defense team who was not on the yacht.

"A lot of people went, a lot of people were planning to go and then of course this happened," Weingarten said.

Some of the people who stood by Lynch throughout the ordeal were on board, including Morvillo, the lawyer, who Weingarten worked with and said "was like a brother."

Morvillo's wife is also missing, according to his law firm Clifford Chance.

Aki Hussain, CEO of international insurer Hiscox Group, where Bloomer, the witness, was chairman, said the company was "deeply shocked and saddened by this tragic event."

"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," he added.

Charlotte Golunski, who survived the disaster, said she momentarily lost hold of her 1-year-old daughter Sofia in the water, but then managed to 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, as did Lynch's wife, Angela Bacares. Hannah Lynch, reportedly the couple's 18-year-old daughter, is among the missing.

The yacht's registered owner is listed as Revtom Ltd., according to online maritime database Equasis. Bacares is listed as Revtom's sole owner, according to corporate registration documents from the Isle of Man.

Its name, Bayesian, may be a reference to "Bayesian Inference," one of the two main approaches to statistical machine learning and the one that was used by Lynch's company.

The yacht, built in 2008 by the Italian firm Perini Navi, was carrying 12 passengers and 10 crew. According to online charter companies, it had been available for charter for 195,000 euros (about $215,000) a week and was notable for its massive 75-meter-tall (246-foot-tall) aluminum mast, one of the tallest in the world.

In an unrelated event, Lynch's co-defendant in the Autonomy trial who was also cleared, Stephen Chamberlain, was killed Sunday when he was hit by a car while running in Cambridgeshire, England, said Chamberlain's lawyer, Gary Lincenberg.

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Winfield reported from Rome. Associated Press writers Eric Tucker in Washington, and Danica Kirka and Kelvin Chan in London, contributed.