The search for survivors of the 180-foot Bayesian has entered its third day, following its sudden sinking near the Sicilian port of Porticello. According to the Independent, two bodies have been found inside the yacht, though they have yet to be identified.

At about 5 am on Monday, a waterspout, or a small, localized tornado on the water, caused the vessel to heel over and eventually capsize, sending it about 165 feet to the bottom of the Mediterranean.

Fifteen people were rescued by a nearby vessel. Authorities have identified the body of Recaldo Thomas, a Canadian Antiguan, who worked as the sailing yacht’s chef. But six others are still missing, including Mike Lynch, a British technology entrepreneur, and his 18-year-old daughter Hannah; Jonathan Bloomer, chairman of Morgan Stanley International, and his wife, Judy Bloomer; and attorney Christopher J. Morvillo and his wife, Neda Morvillo.

The celebratory trip aboard Bayesian took place shortly after Lynch was acquitted of fraud charges in the U.S. in a long-running legal battle against accusations that he had defrauded Hewlett-Packard when he sold his company, Autonomy, for $11 billion.

Prosecutors in the Italian city of Termini Imerse are opening a formal investigation into the yacht’s sinking, according to The New York Times. Divers have so far been unable to verify whether any of the missing are on board.

Boat International has quoted a crew member as saying that the boat was struck by a freak weather event, which caused it to heel 20 degrees on its right side. It continued to heel until it began to take on water and in just 12 minutes. “We just didn’t see it coming,” Capt. James Calfield told Italian media.

An anonymous superyacht captain speculated to Boat International that water entering from the top or through open doors and windows of the boat would have caused the sinking, given that no breaches have been reported in the hull. Some witnesses have said that the mast snapped before the boat sank, but divers report the vessel is intact on the sea bottom.

David Hutchinson, captain of Bayesian’s sistership Rosehearty, both built by Perini Navi, told BI that it was “very difficult to understand what could have overwhelmed a vessel of that size, calling the sailing superyacht series “bulletproof.”

“We’ve been to Antarctica and Chile and we’ve had her in 70 knots of wind,” Hutchinson added. He mentioned that a key difference between the two vessels was Bayesian’s 243-foot-tall mast, one of the tallest in the superyacht world. That would’ve made the vessel heavier and could have added windage during the storm.

Jeremy Bloomer, the twin brother of Morgan Stanley chairman Jonathan Bloomer, told the Independent that air pockets within the vessel might be keeping the missing alive. The boat was designed to trap two large air pockets inside the hull in case it ever capsized. “It’s a slow process and it will take time,” Bloomer said. “So there might be air pockets, but we don’t know. It’s still wait and see, so fingers crossed.”

The rescuers have been able to smash through a glass window in the hull, but so far haven’t been able to reach the cabins. Because of the depths, divers can only stay under water for 10 minutes. The Italian coast guard is also working with unmanned underwater drones as part of the rescue efforts.

Dario Boote, a ship structures and naval architecture professor at the University of Genoa, told The New York Times that he expects a series of lawsuits to determine responsibility. “Clearly, only once the wreck is raised will we know more,” he said.