Italian prosecutors have put under investigation two more crew members of the Bayesian, the superyacht that sank off Sicily last week, killing seven people, their lawyer said on Friday.

The move widens the probe into the tragic shipwreck, for which the ship's captain, New Zealander James Cutfield, is already under investigation for possible manslaughter and culpable shipwreck charges.

Since Wednesday, Tim Parker Eaton — the engineer who was in charge of securing the yacht's engine room — and sailor Matthew Griffith — who was on watch duty on the night of the disaster — are under investigation for the same possible charges, their lawyer said.

“The profile of their possible responsibilities is still unclear, as the investigation has just started,” lawyer Mario Scopesi told The Associated Press.

Scopesi added that both Parker Eaton and Griffith left Italy on Wednesday, along with Cutfield and the rest of the crew.

The three crew members were among 15 survivors of the Aug. 19 sinking that killed British tech magnate Mike Lynch, his daughter Hannah and five others.

Chief prosecutor Ambrogio Cartosio, who is heading the investigation, has said his team will consider each possible element of responsibility including those of the captain, the crew, individuals in charge of supervision and the yacht's manufacturer.

The Bayesian, a 56-metre (184-foot) British-flagged luxury yacht, went down near Sicily, in the Mediterranean. Investigators are focusing on how a sailing vessel deemed “unsinkable” by its manufacturer, Italian shipyard Perini Navi, sank while a nearby sailboat remained largely unscathed.

Prosecutors said the event was “extremely rapid” and could have been a “downburst” — a localized, powerful wind that descends from a thunderstorm and spreads out rapidly upon hitting the ground.

All crewmembers survived except for the chef, but six passengers were trapped in the yacht's hull and died.