Until midnight last Sunday, Matteo Cannia sat on a bench overlooking the sea in Porticello. It was too hot to sleep.

The 78-year-old, a fisherman since he was 10, saw the first flashes of lightning. “I heard the thunder and the wind and decided to go home,” he told me.

“When the storm got worse, everyone woke up. Water came into my friend’s house.”

At around 4:15 a.m. local time, Fabio Cefalù – a fisherman who was supposed to go out on Monday morning but, like others, decided not to – suddenly saw a flare go up.

He changed his mind and went out to sea to find out what was going on. All he found were cushions and floating planks of wood.

A luxury superyacht, the Bayesian, moored just a few hundred metres away, had already sunk.

It all happened in the space of 16 minutes of disaster, chaos and misery, putting a sleepy Sicilian fishing port at the centre of attention.

All but seven of the Bayesian’s 22 passengers had climbed into a life raft when the yacht began to capsize. The others never made it out.

Charlotte Golunski, a British woman, was thrown into the water with her one-year-old daughter Sophie. She said she held her baby in the air with all her might to prevent her from drowning. “It was completely black around me,” she said, “and all I could hear were the screams of others.”

She, her baby and her husband James were among those rescued by a nearby sailboat captain. Stuck in the sinking Bayesian was her colleague Mike Lynch – one of the UK’s top tech entrepreneurs, also known as “Britain’s Bill Gates”.

Luxury turned into terror

Mr Lynch had gathered family, friends and colleagues for an idyllic holiday on his luxury boat: a lavish 56-metre (184-foot) sailing yacht that had won design awards and boasted the world’s tallest aluminium mast.

In June, he was acquitted after a lengthy trial in the US of charges that he fraudulently inflated the value of his company, Autonomy, before selling it to Hewlett Packard in 2011. The trip was planned as a celebration of freedom to mark his rehabilitation in the public eye.

Three days after the yacht sank, his body was recovered from the wreck by divers.

A day later, the body of his 18-year-old daughter Hannah, who was due to start studying at Oxford University next month, was found.

Among the others killed were the president of the investment bank Morgan Stanley, Jonathan Bloomer, and his wife, Judy; Mr. Lynch’s lawyer, Chris Morvillo, and his wife, Neda; and the yacht’s chef, Recaldo Thomas. Mr. Lynch’s wife, Angela Bacares, survived.

The family released a statement expressing their “unspeakable grief” and adding that they are “devastated and in shock.”

How the superyacht sank so quickly, while other smaller vessels nearby survived the storm undamaged, has baffled experts.

At a news conference this weekend — the first public statement from officials since the disaster — local prosecutors said they had opened an investigation into possible crimes of manslaughter and negligent shipwreck.

The region’s prosecutor, Ambrogio Cartosio, told reporters that while the investigation was at a very early stage and no one was being specifically investigated, there were “many possibilities of guilt. It could just be the captain. It could be the whole crew… we are absolutely not ruling anything out.”

A small team of British maritime researchers has also been sent to Sicily to work with their Italian colleagues.

Prosecutors said they now believe a downburst was the weather phenomenon that hit the ship: a localized, strong wind that originates in a thunderstorm and spreads unpredictably.

This contradicts earlier reports that indicated a waterspout or mini-tornado at sea was the cause.

Either way, it’s clear that extreme weather played a major role.

The Crucial 16-Minute Window

The investigation team is of course primarily focused on the behavior of the captain, 51-year-old James Cutfield from New Zealand. He survived, along with eight of his crew, and is being questioned.

“We didn’t see it coming,” he told Italian media, referring to the storm, in his only public comments so far.

The problem is, many others did. Heavy winds and rain were forecast, after days of scorching heat. The head of the company that built the Bayesian, Giovanni Costantino, told me he was convinced there were a whole series of errors on board.

“A hatch must have been left open at the back of the boat,” he said, “but perhaps also a side entrance through which water could have flowed in.

“Before the storm broke, the captain should have closed all the openings, weighed anchor, started the engine, pointed to the wind and lowered the keel.”

A keel is a large, fin-shaped part of the boat that extends from the base.

“That would have stabilized the ship so they could have weathered the storm and continued their journey in comfort,” he said.

Rescuers found the wreck of the Bayesian ship 50 metres underwater, with its nearly 10-metre-long keel up.

Had it been deployed, it could have helped counter the winds battering the Bayesian’s 75-metre (246-foot) aluminium mast and kept the ship stable. But without it, experts told La Repubblica newspaper, gusts of 100 kilometres per hour (62 mph) would have been enough to capsize the ship – and Monday’s storm far exceeded that.

“The Bayesian was a model for many other vessels because of its stability and exceptionally high performance,” Mr. Costantino said. “There was absolutely no problem with it. If water had not come in, it would have been unsinkable.”

He told me that there were 16 minutes between the time the ship’s power went out at 3:56 a.m. (indicating that water was flooding areas with electrical circuits) and the time the GPS signal went out, indicating that the ship had sunk.

That period and any measures taken to limit the extreme weather will be further examined by researchers, especially once they find the ship’s black box.

Rino Casilli, one of Sicily’s top marine inspectors, also believes that mistakes have left the yacht vulnerable to the extreme weather conditions.

“There should have been two crew members taking turns on watch, given the storm warning,” he told me as he took me out on his boat—about a third the size of the Bayesian. “And it should have been moored in the harbor, not out at sea.”

It has not yet been determined how many people were on guard that night.

From his sailboat we had rare access to the spot where the Bayesian wave was descending.

An Italian police ship was circulating around us, warning us. Suddenly there was a flurry of activity among divers, while other rescue ships arrived.

We didn’t know it at the time, but they had just found more bodies.

It was a hugely challenging operation for the teams to recover the prisoners from the wreck. Given the depth, 50 meters under water, each diver was allowed to go down for 10 minutes before surfacing for their own safety – a total of 120 dives. They were assisted by remote-controlled vehicles that could operate on the seabed for much longer.

Rescue workers said at this weekend’s press conference that passengers trapped during the sinking sought refuge in cabins on the left side of the ship, where the last air bubbles were forming.

Five of the bodies were found in the first hut on the left, they said, while the last body – confirmed as Hannah Lynch – was in the third hut on the left.

Access for emergency services was extremely difficult as the yacht was largely intact and furniture obstructed access.

The Coast Guard compared it to an “18-story building full of water.” As Ms. Lynch’s body was brought to shore, rescuers in the harbor applauded their colleagues.

All seven dead have been taken to a morgue for autopsy.

Rescuers must now decide whether – and how – to salvage the wreck, which would undoubtedly yield vital clues to what happened. But bringing the Bayesian to the surface could take six to eight weeks and cost 15 million euros (£12.7 million), according to some estimates.

The hunt for clarity

While the divers’ painstaking work to recover the dead has been completed, the investigators’ arduous search for answers has only just begun.

She and the survivors are in a hotel near Porticello, which is strictly off-limits to journalists. Security guards promptly asked us to leave.

Solving the mystery of what happened to the Bayesian is not only vital to helping victims’ families gain closure, but also to allow the maritime industry to draw conclusions.

The brother of James Cutfield, the captain, said he was a “highly respected” sailor who had worked on boats all his life. Did the veteran sailor somehow make a series of catastrophic mistakes? The Nautilus union, which represents seafarers and captains, called for restraint in passing judgment on the Bayesian’s crew.

“Any attempt to cast doubt on their conduct without all the facts is not only unfair but also damaging to the process of establishing the truth and learning lessons from this tragedy,” the report said.

The world’s media is beginning to leave Porticello, which is slowly returning to the tranquility of its pre-Bayesian era. Stray cats roam among the old fishing boats and children play as their families dine out in the few seaside restaurants.

But what happened over the past week has shocked and scarred many here.

“Last Sunday night we saw the end of the world in Porticello,” said resident Maria Vizzo. “We have never seen anything like it. Everyone here is shocked – and everyone is crying.”

More about this story