It’s understood that four of the people who died when a superyacht sank suffocated as oxygen ran out.

In the early hours of August 19, a luxury Bayesian yacht sunk not far from the northern coast of Sicily after running into a sudden, violent storm.

There were 22 passengers on board the 56-metre boat when it began sinking ‘rapidly’ with 15 surviving, including captain James Cutfield.

Tech entrepreneur Mike Lynch and his 18-year-old daughter Hannah were two of the seven fatalities, as well as Clifford Chance lawyer Chris Morvillo and his wife, Neda.

International Chairman of Morgan Stanley Bank Jonathan Bloomer, his wife Judy Bloomer and yacht chef Recaldo Thomas were also listed among the deceased.

It was previously believed that all seven people had died from drowning, but it’s now been claimed by local media that the Bloomers ‘suffocated’ to death after oxygen ran out in an air bubble.

According to Italian outlet La Repubblica, a post-mortem conducted on Jonathan and his wife found their lungs ‘not fully of water and neither were their stomachs or trachea’.

A post-mortem has suggested Jonathan Bloomer and his wife Judy’s manner of death (Family Handout)

The newspaper further suggests the pair had briefly survived the tragedy below deck.

It is suggested that they’d possibly moved into a ‘small’ air pocket that would have ‘quickly filled with rising levels of toxic carbon dioxide’.

Sky News reports that divers who recovered bodies from the yacht allegedly found them on the left side of cabins.

Investigators claim their positioning showed them seeking the last pockets of air as the vessel tilted to the right after sinking.

La Repubblica added that neither the Bloomers nor the Morvillos showed any sign of injuries.

15 of the 22 people on board the vessel survived the tragedy (ALBERTO PIZZOLI/AFP via Getty Images)

Further post-mortems are expected to be carried out later this week on businessman Lynch, his daughter and Thomas.

It’s reported that the vessel, built by Italian yacht manufacturer Perini, will also be lifted from the seabed as part of the ongoing investigation into the tragedy.

At the time of writing, the vessel is thought to be 50 meters underwater in the bay of Porticello.

Elsewhere, Italian prosecutors are reportedly investigating the boat’s 51-year-old captain Cutfield for possible manslaughter and shipwreck charges.

It’s understood British engineer Tim Parker Eaton and sailor Matthew Griffiths are also under investigation for the same charges.

Mike Lynch and his daughter Hannah were among the deceased (PA)

Giovanni Rizzuti, one of two legal representatives appointed to defend the vessel’s captain, said his client has been ‘deeply affected by this ordeal’.

“We are currently assessing, with other legal representatives, the defence strategy and examining the technical aspects of the case.”

Under Italian law, being under investigation does not imply guilt and doesn’t mean that charges will follow as there may be more people who are also under investigation.