James Cutfield was questioned for more than two hours after the deaths of tech tycoon Mike Lynch, 59, his daughter Hannah, 18, and five others.
Prosecuting magistrates, who spoke to the New Zealander for the second time in a week, said that he had been "extremely co-operative" in answering questions.
Investigators may also interview a crew member who was on watch and survived when the storm hit off Porticello, the Italian press reported.
In Italy being placed under investigation does not imply guilt and does not mean formal charges will follow.
Key crew members have stayed in Sicily voluntarily to help authorities.
Six passengers and chef Recaldo Thomas died when the British-flagged vessel capsized in a freak storm on August 19. The 184ft-long yacht, which had the world's tallest aluminium mast at 246ft, is thought to have been hit by a "downburst".
Denne historien er fra August 27, 2024-utgaven av Daily Express.
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Denne historien er fra August 27, 2024-utgaven av Daily Express.
Start din 7-dagers gratis prøveperiode på Magzter GOLD for å få tilgang til tusenvis av utvalgte premiumhistorier og 9000+ magasiner og aviser.
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THE ART OF WAR
Boss lauds 'ugly' derby win after sleepless nights blight build-up
CLOCK-WISE
Newcastle wake up in time to stun dominant Wolves
Vu's late burst ends brave European rally
LILIA GETS AMERICANS OVER LINE
'Miracle' Triple Layer Insoles stopped my husband's knee and foot paint!
They also turned him from a grumpy old grouch to being active, pain-free and happy again! And got my life back too!
Why teens are hooked on Friends 20 years on
The one where a new generation of fans is devoted to the hit TV show three decades after it first aired... Debbi Marco takes her children to an immersive experience bringing the iconic TV sitcom back to life
FINAL JOURNEY OF THE UNKNOWN WARRIOR
In the final extract from his impossibly moving new book, RAF veteran John Nichol reveals how the remains of ONE anonymous fallen serviceman were chosen to represent ALL of Britain's First World War missing
Space billionaire returns to Earth with a splash
THE first non-astronaut to walk in space landed back on Earth yesterday after an epic five-day trip.
'I feel I'm having one of the greatest decades of my life'
DAVINA McCall is relishing fulfilling lifelong her 50s career ambitions, scooping an MBE and finding happiness with partner Michael Douglas.
Putin hands Iran nuclear secrets in return for ballistic missiles
FEARS were growing in the West last night that Russia gave Iran nuclear secrets in return for ballistic missiles to use in its bombardment of Ukraine.
William wishes Harry a happy 40th birthday
KATE and William sent greetings to Prince Harry on his 40th birthday yesterday as they followed the lead of the King.
