The MH370 Independent group that has been investigating the disappearance of the Malaysia Airlines flight previously suggested that the pilot may have tried to deceive radar operators into believing that the plane had intended to land.

Christine Negroni, author of Crash Detectives: Investigating the World's Most Mysterious Air Disasters, has suggested that the co-pilot of the doomed MH370, Fariq Abdul Hamid, attempted to land the aircraft at Malaysia’s Langkawi Airport before it crashed into the ocean, Daily Star reported.

"I found it interesting the plane was heading towards Langkawi, and he's got an airplane that's full of fuel. So, part of his plan is thinking I'll put an airplane down at an airport I know, some habit comes back to his mind, that's why he's heading there. Langkawi, that's where he learned to fly and that's the point he turned west”, she told Daily Star Online.

She, however, made an assumption that the co-pilot failed to land the plane safely because it has depressurised, while captain Zaharie Ahmad Shah was using the bathroom.

It was widely reported that Fariq Hamid had graduated from Langkawi Aerospace Flying Academy, situated some 700 metres from the airport's runway, which made Negroni suggest that he tried to land there because it was so familiar.

Instead of landing at Langkawi, the aircraft kept moving west before it turned left, eventually crashing into the Indian Ocean after running out of fuel, experts have determined.

According to Negroni, the reason behind the pilot’s inability to land the plane was hypoxia – oxygen deficiency – caused by depressurisation.

"So what happened? Why did it fail to revive him? Why didn’t Capt. Zaharie return to the cockpit? Everything was in chaos, the altitude warning alarm still clanging. I find it logical to assume Zaharie visited the business-class bathroom near the flight deck that is also used by the flight crew. In this and all of the airline’s 777’s bathrooms, a drop down mask is there to provide oxygen in the case of depressurization”, Negroni wrote in her book, published by Atlantic Books in the UK.

She then continued by trying to imagine what could have possibly happened there:

“Imagine what it would be like for Zaharie to see the yellow plastic cup bob down after the depressurisation. He would have been momentary rattled but with his experience, he would have realised immediately what happened and what needed to be done. Still, he had to make a choice: try to get back to the cockpit without supplemental oxygen, or remain in the bathroom and wait for Fariq to get the airplane to a lower altitude and then rejoin him on the flight deck”.

Her guess is that the captain was not sure that Fariq was able to handle the emergency, “and chose the former course of action. But the effect of oxygen deprivation was crippling Zaharie, too”.

"Air was exploding from his respiratory and digestive systems. His extremities were shaking. He struggled to get out of the bathroom. Perhaps he looked for a flight attendant or a portable oxygen tank. Perhaps he stopped to assess the situation in the cabin. Perhaps he retained focus and moved quickly to the cockpit door”.

READ MORE: Doomed MH370 Wreck Could Finally Be Found as Enthusiast Starts New Hunt

She noted that the fact that both Fariq and Zaharie were smokers could have made them more susceptible to the effects of hypoxia:

"If he got out of the bathroom, if he got down the narrow corridor, if he got to the door of the cockpit without losing consciousness or cognitive function, another challenge would await him. The cockpit door unlocks automatically when cabin altitude is lost. Would Zaharie have remembered that? Or did he, by force of habit, stop outside the door and try to enter the code? Did he lose precious seconds struggling to remember a passcode he did not need? Or did he just grab the handle and open the door but succumb to the lack of oxygen before getting into his seat?”

Negroni then made a reference to accounts of pilots at Malaysia Airlines, who told her that it would be difficult for the captain to get back onto the flight deck in a rapid decompression.

"All the previous cases of rapid depressurisation on airliners, those that successfully landed and the few that crashed, bring home with chilling clarity that physical exertion eats away at the too-few seconds of useful consciousness. The captain was unable to regain command of the airplane. If he had, things might have turned out very differently".

A widely popular theory suggests that one of the pilots was behind the plane’s disappearance. Aviation expert and former investigator with the Transportation Safety Board of Canada Larry Vance said last May he believed that the MH370 was intentionally flown into the ocean in an act of murder-suicide.

Australian Prime Minister Malcolm Turnbull also alleged in 2016 that it was “very likely that the captain planned this shocking event”.

Beijing-bound Malaysia Airlines Flight MH370 with 239 passengers and crew on board went off radars on 8 March 2014. After years of botched attempts to find the site of the wreckage, the Malaysian government stopped the investigation, having acknowledged that they did not know what had happened to the airplane.

Despite an extensive search operation conducted jointly by Malaysian, Chinese and Australian investigators, only a few pieces of debris thought to be parts of the wreckage have been discovered at different locations, including South Africa, Mozambique, and the French Island of Reunion in the Indian Ocean.

READ MORE: Families of MH370 Passengers Call for Resuming Search Amid Finding of New Debris

In late November, several new pieces of debris allegedly belonging to the doomed MH370 airliner were reportedly found off the coast of Madagascar.