Specialist divers on Tuesday launched a fresh search for six people, including UK tech tycoon Mike Lynch and the chairman of Morgan Stanley International, missing since their yacht capsized off the Italian island of Sicily.
The British-flagged Bayesian, which had 22 people aboard including 10 crew, was anchored some 700 metres from port before dawn Monday when it was struck by a waterspout, a sort of mini tornado.
Fifteen people aboard, including a mother with a one-year-old baby, were plucked to safety; one man has been found dead; and six people remain missing.
On Tuesday, three divers strapped on oxygen bottles and began their descent to the wreck, some 50 metres below the sea surface.
Most of those aboard the yacht were British, and the passengers were guests of Lynch, celebrating his recent acquittal in a massive US fraud case, according to Italian media.
Lynch's wife Angela Bacares was among 15 people rescued, but the businessman and his 18-year-old daughter Hannah were missing, according to Salvo Cocina, head of the Civil Protection Agency in Sicily.
The chair of Morgan Stanley International, Jonathan Bloomer, who testified for Lynch, was also missing alongside his wife, Judy, the UK insurer Hiscox said on Tuesday.
Bloomer is also the chair of Hiscox, which issued a statement saying it was "deeply shocked and saddened" by the incident.
Christopher Morvillo of law firm Clifford Chance, who represented Lynch, had also been on the boat along with his wife, media reports said.
Lynch, 59, is a celebrated technology sector entrepreneur and investor, sometimes referred to as the UK's answer to Bill Gates.
Lynch was acquitted on all charges in a San Francisco court in early June after he was accused of an $11 billion fraud linked to the sale of his software firm Autonomy to Hewlett-Packard.
Divers trained to work in tight spaces were flown in from Rome and Sardinia late Monday, but a first, nighttime search of the wreck failed.
"Access was limited only to the bridge, with difficulty due to the presence of furniture obstructing passage," the fire service said on X.
The 56-metre (180-foot) long luxury vessel was moored off Porticello, east of Palermo, when violent winds and rains suddenly swept up the coast.
"It was terrible. The boat was hit by really strong wind and shortly after it went down," survivor Charlotte Golunski told ANSA news agency.
Golunski, board director at Luminance, a company founded by Lynch, lost hold of her one-year-old daughter in the waves "for two seconds", before managing to grab her "while the sea raged".
"Lots of people were screaming" in the dark, said Golunski, who managed to get on a life raft.
A waterspout is a column that descends from a cloud to form a rotating mixture of wind and water over a body of water, often during severe thunderstorms.
Just a few hours later, the seas were calm as divers recovered a body, reported to be the yacht's chef.
They also spotted a body inside the sunken vessel, a source close to the recovery operation said.
The Bayesian was a superyacht built by the Italian shipbuilding firm Perini Navi in 2008 which boasted a 75-metre mast, the tallest aluminium sailing mast in the world, according to the Charter World website.
Karsten Borner, the captain of another yacht anchored nearby at the time of the storm, said there was a "very strong hurricane gust" and he had to battle to keep his vessel steady.
He saw the Bayesian's mast "bend and then snap", according to Italy's Corriere della Sera daily.
Italian authorities have opened a probe into the incident.
