All 227 passengers on Malaysian Airlines Flight MH370 have been cleared of any foul play involving the disappearance of the Boeing 777.

Inspector-General of Police, Tan Sri Khalid Abu Bakar, said that all passengers on the international flight were cleared of hijacking, sabotage, psychological, and personal problems. Police are still investigating the cabin crew, pilot and co-pilot, all Malaysian citizens.

On Tuesday, Bakar said that he and his investigators had “obtained some clues” as to what happened to Flight 370, but refused to elaborate to keep the investigation from being jeopardized.

“We don’t know how long the investigation will take… and the reason behind all this might not be uncovered… (but) that is why it is ongoing,” Bakar said.

Flight 370, which took off from Kuala Lumpur International Airport on March 8, never arrived at its destination, Beijing Capital International Airport. It lost contact with air traffic control less than an hour after takeoff.

It was initially believed that the airliner crashed in or near the Gulf of Thailand but, as weeks passed, the search area shifted to the Strait of Malacca, Andaman Sea, and Indian Ocean. So far, no confirmed debris has been recovered.

As well as investigating the crew, authorities are also looking into other possibilities such as tampering of the cargo or food or a mechanical disaster.

Former civil aviation security chief, Billie Vincent, believes that the disaster could have been started by a fire.

“My guess is that in the horrendous conditions that this crew was operating when they were turning that airplane was that the cockpit is full of smoke, you can’t even see the instruments. As opposed to being hijackers, the crew were heroically trying to save the airplane, themselves and the passengers when this catastrophe hit,” Vincent said.

But if the crash, specifically the flight data recorder, is not found soon, the disappearance of Malaysian Flight 370 could forever remain a mystery.

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