After a lengthy investigation, including more than 170 interviews, Malaysian police have cleared all of Flight MH370's occupants of wrongdoing, except for the pilot.

Captain Zaharie Ahmad Shah remains a suspect in the disappearance of the plane, which vanished on March 8 while traveling from Kuala Lumpur to Beijing with 239 persons on board.

Police told London's Sunday Times that Shah had a flight simulator at home that was programmed with practice flights to a remote island in the south Indian Ocean. He also allegedly practiced landing on a shortened runway, and flying long distances across the Ocean. The programs were deleted, but authorities were able to recover the data.

Authorities also said that Shah, unlike the other crew and passengers, had no business or personal plans scheduled in his datebook for after the flight, according to the Mirror.

There are also claims that the 53-year-old was an extreme supporter of Malaysian Leader of Opposition Anwar Ibrahim, who was found guilty of sodomy in an appeals court just hours before Flight 370 went missing. Shah attended Ibrahim's trial, then immediately went to the airport.

In addition, one of Shah's friends, also a pilot, told reporters in March that the captain had been under mental duress.

"He's one of the finest pilots around and I'm no medical expert," the friend told the New Zealand Herald, "but with all that was happening in his life, Zaharie was probably in no state of mind to be flying."

Allegedly, Shah's marriage was falling apart, and he was also having problems with his girlfriend. Shah's brother-in-law, Asuad Khan, denied those claims last month – saying that Shah "had a good life," and the reports that implicate him in the plane's disappearance are false.

"I can see that a lot of people are saying a lot of things about him which is untrue," he told ABC Australia.

"He had a lot of money, and he loved his daughter very much."

Police are still considering terrorism and mechanical failure as causes for the plane's disappearance. To date, no debris or evidence of a crash site have been found.