PORTICELLO, Sicily (AP) — Rescuers searching the wreck of a superyacht that sank off Sicily brought ashore a fifth body on Thursday, leaving one person still unlocated, as investigators sought to learn why the vessel sank so quickly.

Rescue crews brought the body bag ashore at Porticello port while divers continued to search for the sixth missing person, whom the coast guard identified as a woman. That suggested that the recovered bodies included that of British tech magnate Mike Lynch.

Also among the six missing passengers were Lynch’s 18-year-old daughter and associates who had successfully defended him in a recent U.S. federal fraud trial.

No signs of life have emerged over four days of searching the yacht’s hull on the seabed 164 feet (50 meters) underwater.

The Bayesian, a 56-meter (184-foot) British-flagged yacht, went down in a storm early Monday as it was moored about a kilometer (half mile) offshore. Civil protection officials said they believe the ship was struck by a tornado over the water, known as a waterspout, and sank quickly.