Baku, March 21 (AZERTAC). The Malaysian authorities say some data was deleted from a flight simulator that one of the pilots of the missing Malaysia Airlines jet had built in his home, and they have turned to the FBI for help in recovering the data, in the hope that it will provide some clue to what happened to the plane.

The expansion of the American role in the investigation came as governments struggled to narrow down the vast search zone for the plane, which stretches across two hemispheres.

According to investigators, the jetliner most likely flew into the southern Indian Ocean. “The working assumption is that it went south, and furthermore that it went to the southern end of that corridor,” said a source.

It was not clear whether the Malaysians have asked American law enforcement officials for help with any other parts of their inquiry.

The Malaysians have kept American investigators at a distance since the plane vanished in the early hours of March 8, angering some lawmakers in Washington who believe the FBI should have been playing a larger role in the investigation from the beginning. A small team of FBI agents in Malaysia has received briefings on the investigation, but have not been asked to help with the inquiry.

Despite this, American law enforcement officials and intelligence analysts in Washington checked the names of the passengers on the plane to determine whether any of them had known links to terrorists, but that yielded no connections.

As part of the American efforts, FBI agents interviewed family members of the passengers in the US and Europe, and conducted link analysis — a computer-based investigative technique that tries to discern connections between individuals based on extensive government and airline databases — on the pilots and on two Iranian passengers who were travelling on stolen passports.

Investigators have said the plane’s extraordinary diversion from its intended course, from northeastward across the Gulf of Thailand to westward across the Malaysian peninsula, was probably carried out by someone on the plane who had aviation experience. Attention has focused on the two pilots — Captain Zaharie Ahmad Shah, 53, and his junior officer, Fariq Abdul Hamid, 27.

The Malaysian police, who found that Zaharie had a flight simulator in his home, said today that some data was erased from the simulator on February 3, more than a month before the ill-fated flight.

“The experts are looking at what are the logs, what has been cleared,” Tan Sri Khalid Bin Abu Bakar, inspector-general of the Malaysian police, told reporters at a news conference in Sepang, on the outskirts of Kuala Lumpur, the capital. He declined to comment further.

Because of evidence suggesting that whoever diverted the missing plane, a Boeing 777-200, knew how to disable the plane’s communications systems and make course changes, the data recorded in Zaharie’s flight simulator may shed light on whether he was involved, and may have rehearsed such actions before the flight.

But building and using flight simulators at home is a popular hobby among aviation enthusiasts, and the deletion of data from his simulator may have been routine housekeeping with no significance.

Hishammuddin Hussein, the Malaysian defence minister and acting transportation minister, emphasised that “the passengers, the pilots and the crew remain innocent until proven otherwise”.

He said the authorities had received background-check information from the home countries of all the passengers on the plane except Ukraine and Russia. “So far, no information of significance on any passengers has been found,” he said.

The 12 days since the plane, Malaysia Airlines Flight 370 bound for Beijing from Kuala Lumpur, disappeared from air controllers’ screens have been troubled by confusion that has compounded the anguish of family members.