Italian rescue divers have found the body of the last person missing after British tech magnate Mike Lynch’s family yacht sank off Sicily, believed to be his daughter Hannah, a source close to the matter told Reuters on Friday. The British-flagged Bayesian, a 56-metre-long (184-foot) luxury sail boat carrying 22 passengers and crew, was anchored off the port of Porticello, near Palermo, when it capsized and rapidly sank after being struck by a pre-dawn storm on Monday. The source did not identify the body as belonging to 18-year-old Hannah Lynch, but she was the only person still unaccounted for.

Italian news agency Adnkronos said she was found inside the yacht. The wreck is lying at a depth of 50 metres and once inside the passageways are narrow. The fire brigade on Friday described rescue operations as “long and delicate”, and said they involved more than 400 people, including 28 specialist divers.

The bodies of the other five dead passengers, including Lynch, were recovered on Wednesday and Thursday from inside the yacht. The body of the only crew member who died, onboard chef Recaldo Thomas, was found near the wreck on Monday. Official identification of the corpses and autopsies are expected to begin after the transfer of the last recovered body to a hospital morgue in Palermo.

A judicial investigation has been opened into the sinking, which has baffled naval marine experts who say a boat like the Bayesian, built by Italian high-end yacht manufacturer Perini, should.