A woman leaves a message of support and hope for the passengers of the missing Malaysia Airlines MH370 in central Kuala Lumpur, March 16, 2014. Reuters/Damir Sagolj/File Photo

French investigators have reportedly claimed that a mysterious “third entity” may be withholding technical data about the path taken by missing Malaysia Airlines Flight MH370 the day it disappeared. The Boeing 777-200 went missing on March 8, 2014, with 239 people on board while on its way from Kuala Lumpur to Beijing.

Despite several efforts to find the plane, the mystery behind its disappearance continues. However, there have been several theories as to what happened to Flight MH370. On Wednesday, a report claimed that French investigators identified a number of “curious passengers” aboard the plane who they believe must be investigated.

Ghyslain Wattrelos, a French national who lost his wife and two teenage children on MH370, made the claims following his meeting last week with judges overseeing the Gendamarie Air Transport (GTA) investigation.

Wattrelos said he was told the French team had found “inconsistencies” in the Malaysian investigation’s official report released in July and identified the presence of “curious” passengers, whom “we should continue to investigate.”

According to the French team, a Malaysian national and aeronautics specialist was seated directly under MH370’s Satcom -- the antenna that communicates to the Inmarsat satellite from the aircraft -- module and had the potential and technical knowledge to hack the plane’s communication systems and disguise its route. The identity of the “third entity” is unclear.

The GTA, a part of the French military, is seeking to verify satellite and other technical data used by the Australian Transport Safety Bureau (ATSB) to find details about the flight path the missing plane took before crashing in a remote part of the southern Indian Ocean.

Wattrelos said investigators hoped to travel to the U.S. to meet with the FBI, which examined MH370 Captain Zaharie Shah’s home flight simulator.

A similar trip planned in September 2017 was canceled after U.S. authorities demanded the signing of “confidentiality clauses” to protect Boeing “industry secrets.” French investigators had identified a “third entity” in possession of information or data relating to the movements of the missing plane.

“We are a little angry and now we want to say stop, it is time that the United States really cooperate on this issue,” Wattrelos said. “It is necessary to go there because there are three entities that hold important information for understanding what happened on this flight.”

Investigators were also seeking to establish whether the “third entity” sold software capable of reprogramming or even hacking the Satcom.

“The essential trail is the Inmarsat data. Either they are wrong or they have been hacked,” Wattrelos said. “However, these satellite data are essential to better understand the trajectory of the aircraft.”

The identity of the “third entity” is unclear, but Wattrelos refers to SITA -- a company which supplies Malaysia Airlines with communications via VHF radio and Inmarsat satellites for its fleet’s ACARS (Aircraft Communications Addressing and Reporting System) avionics -- in a Facebook post.

“It’s not clear what additional information the French investigators expect to obtain while in the US. Boeing has co-operated with the Annex 13 investigation team, and is unlikely to provide private French investigators with data that has not already been made public,” engineer and aviation expert Dr. Victor Iannellohe wrote on his blog.

“The mysterious ‘third entity’ referred to by Mr Wattrelos that might be selling software capable of maliciously altering SATCOM data is also unknown, although there are a handful of companies in the US and Canada that supply hardware and software for designing, building, and testing parts of the Inmarsat network,” Iannellohe added.

As the mystery deepens, families of those on board the missing jetliner are still waiting for a closure as they too suspect a major cover-up by governments involved in the search of the plane.

While there is no concrete clue as to the whereabouts of the plane, a British investigator Ian Wilson who claimed to have spotted Flight MH370 on Google Maps in a Cambodian jungle recently made a trip to the area to prove his claim.

However, the mission had to be aborted due to the dangerous path leading up to the alleged crash location.