A book on the ill-fated flight MH370 suggests that passengers died of oxygen deprivation before the pilot Ahmad Shah ditched the plane into the Indian Ocean.
The theory is the result of the first independent study into the disaster by the New Zealand-based air accident investigator, Ewan Wilson.
Wilson, a commercial pilot and founder of Kiwi Airlines, came to the conclusion after considering "every conceivable alternative scenario".
He suggests that all 239 people on board lost consciousness up to four hours before the Boeing 777 mysteriously disappeared and whose whereabouts are still unknown.
Wilson claims the most likely scenario is that pilot Zaharie Ahmad Shah deliberately depressurised the cabin, depriving those on board of air.
Oxygen masks would have dropped down automatically from above the seats, but the supply was just 20 minutes. Sleeping passengers would have passed out within a few minutes, slipped into coma and died soon after from oxygen starvation.
However, many critics say Wilson is unable to provide any conclusive evidence to support his theory. An earlier report from the Australian Transport Safety Bureau concluded that passengers may have died from hypoxia.
The claims are made in the book Goodnight Malaysian 370, the result of a four-month study which was co-written with New Zealand journalist, Geoff Taylor.
"One of our objectives in writing this book was, in some small way, to convey the human stories of the tragedy," said Wilson.
"Neither could we have imagined the horrific scenario that our research suggests took place on board that fateful plane."
Among the book's claims is that the senior pilot Ahmad Shah was suffering from mental illness, and persuaded his co-pilot Fariq Hamid to take a break about 40 minutes after take-off.
After locking Hamid out of the cockpit, Ahmad Shah made the last known message to air traffic control, "Goodnight, Malaysian 370" before switching off the aircraft's air-to-ground communication links.
The Australian government set aside almost $90m for the search, expected to be the most expensive in aviation history.