The body of British tech entrepreneur Mike Lynch was recovered Thursday from his family's superyacht that sank off the coast of Italy after it encountered a sudden and powerful storm, authorities said.

After four bodies were recovered from the wreck Wednesday, Lynch's 18-year-old daughter, Hannah, remains the only person unaccounted for, Massimo Mariani, of Italy's interior ministry, told Reuters. Her body may have been swept out to sea, Mariani said.

It could take divers more time to find her body because of the difficulties of accessing the sunken ship more than 160 feet down, said Luca Cari, a fire brigade spokesperson. Rescuers faced a challenging task in scouring extremely deep and narrow spaces around the boat.

Giovanni Costantino, the CEO of Italian ship manufacturer Perini, which made the ship in 2008, told Reuters on Thursday, "The boat suffered a series of indescribable, unreasonable errors."

He said the crew made an "incredible mistake" in not preparing for the storm, even though it was announced in a shipping forecast earlier. "This is the mistake that cries out for vengeance," he said.

Lynch, 59, was best known as the co-founder of Britain’s largest enterprise software, Autonomy, which was sold to Hewlett-Packard in 2011. He had invited his friends on the yacht to celebrate his acquittal in June of fraud charges related to the sale of Autonomy.

The Bayesian, a 184-feet-long British-registered sailboat, went down just before sunrise Monday off the coast of Porticello, near Palermo, where it was anchored when a strong storm swept across the area. Of the 22 passengers and crew members on board, 15, including Lynch's wife, Angela Bacares, were pulled from the water Monday, and several were hospitalized. Divers then recovered the body of Ricardo Thomas, the yacht's chef, near the ship.

Who were among the missing?

An exhaustive search ensued for six missing people: Lynch and his daughter; Judy and Jonathan Bloomer, a non-executive chair of Morgan Stanley International; and Clifford Chance lawyer Chris Morvillo and his wife, Neda Morvillo.

Jonathan Bloomer was a character witness at Lynch’s fraud trial, and Chris Morvillo, an American citizen, was part of the team that represented Lynch.

Hannah, the younger of Lynch's two daughters, was preparing to study English literature at Oxford University, according to the Sunday Times.

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Investigation opened into the tragedy

Local prosecutors have opened an investigation into the disaster and will hold a press conference on Saturday.

Costantino said there were no errors in the ship's construction or design. "It went down because it took on water. From where, the investigators will tell," he said.

The ship, owned by Lynch's wife, Bacares, was constructed in accordance with international maritime standards and commercially certified by the U.K.'s Maritime and Coastguard Agency, according to Matthew Schanck, chairman of the Maritime Search and Rescue Council. It was refitted for the second time in 2020.

Experts have pointed to a waterspout, a tornado over the water that can travel up to 120 mph, that formed during the storm, as well as the weight of the ship's mast, one of the largest in the world, as possible factors in its sinking.

Contributing: Jeanine Santucci, USA TODAY; Reuters