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Search operations resumed early on Thursday

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Five bodies retrieved from sunken superyacht

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Victims not yet named by Italian authorities

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Prosecutors investigating the cause of the sinking

(Recasts lead, adds fifth body found in second paragraph)

PORTICELLO, Italy, Aug 22 (Reuters) -

Italian rescue divers were scouring the sunken family yacht

of British tech magnate Mike Lynch on Thursday for one last

missing body, three days after the luxury vessel capsized in a

violent storm off the coast of Sicily.

Earlier in the morning members of the fire brigade and the

coast guard recovered a fifth corpse, after four bodies were

retrieved from the wreck on Wednesday and transported to nearby

hospitals, in the city of Palermo.

Italian authorities did not officially identify the corpses,

but Britain's Daily Telegraph reported that two of the dead were

Lynch and his 18-year-old daughter. Italy's Corriere della Sera

said the only bodies identified so far were Morgan Stanley ( MS )

banker Jonathan Bloomer and U.S. lawyer Chris Morvillo.

The British-flagged Bayesian, a 56-metre-long (184-ft)

superyacht carrying 22 passengers and crew, was anchored off the

port of Porticello, near Palermo, when it disappeared beneath

the waves in a matter of minutes after a fierce storm struck.

Fifteen people, including Lynch's wife, managed to escape

the boat before it capsized, while the body of the onboard chef,

Canadian-Antiguan national Recaldo Thomas, was found near the

wreck hours after the disaster.

Operations have been challenging due to the depth and the

narrowness of the places that the divers are scouring, the fire

brigade said in a statement.

It compared the efforts to those carried out, on a larger

scale, for the Costa Concordia, the luxury cruise liner that

capsized off the Italian island of Giglio in January 2012,

killing 32 people.

UNSINKABLE

The disaster has baffled naval marine experts who said such

a vessel, built by Italian high-end yacht manufacturer Perini

and presumed to have top-class fittings and safety features,

should have been able to withstand such weather.

Prosecutors in the nearby town of Termini Imerese have

opened an investigation and authorities have started questioning

passengers and witnesses.

The captain, James Cutfield, and crew have made no official

comment on the disaster.

Giovanni Constantino, CEO of the Italian Sea Group

, which includes Perini, said the Bayesian was "one of

the safest boats in the world" and basically unsinkable.

He added that he believed the disaster was caused by a chain

of human mistakes and that the storm had been expected, in

interviews with Italian media.

"The ship sank because it took on water, from where

investigators will have to say," Constantino told television

news programme TG1 late on Wednesday.

Citing data from the yacht's automatic tracking system and

based on available footage, Costantino said it took 16 minutes

from when the wind began buffeting the yacht and it began taking

on water for it to sink.

Constantino said the Milan-listed group had suffered

"enormous damage" to its reputation, with shares falling 2.5%

since the disaster.