The pilot of doomed flight MH370 was "in control until the very end", it has been claimed by authorities investigating the case.
Evidence is mounting the crash, which has become of the greatest aviation mysteries of all time, was a murder-suicide.
New flight data suggests "some abnormal turns [were] made by the 777 [that] can only be done manually."
So, French investigators claim captain Zaharie Ahmad Shah was a troubled, lonely man who deliberately killed all passengers and crew on board the flight.
But it will take around "a year" to go through all of the information received from Boeing.
A source, who is "close to the investigation", said: "Some abnormal turns made by the 777 can only be done manually. So someone was at the helm.
"It is too early to state categorically. But nothing is credited that anyone else could have entered the cockpit."
The informant told Le Parisien the new development amid France's judicial inquiry into the crash. It is the only country to conduct one as of yet.
Ghyslain Wattrelos, a Frenchman who lost his wife and two teenage children on the flight, praised the investigators saying he was "delighted" with the work which had been carried out.
"I hope that by analysing all the data collected at Boeing , they will discover a problem that will be obvious to them.
"For now, they provide incredible work that allows to evacuate some tracks, but is not conclusive," he told the publication.
In the past, theorists have suggested Russians stole the plane and flew it to Kazakhstan, or that it suffered a catastrophic systems failure.
But last month, it was alleged Shah incapacitated or killed his co-pilot.
It was claimed he took control of the plane, depressurised the cabin to kill everyone on board and then steered the Boeing 777 out to sea where he either waited for it to run out of fuel, or deliberately nose-dived it into the ocean.
And last year, an eagle-eyed dad spotted what looked like an underwater airliner on Google Earth .
Robert Morton, 55, suggested it may have been the doomed plane .
