The pilot of missing Malaysia Airlines flight MH370 is now the prime suspect for the jet's mysterious disappearance.

Captain Zaharie Shah, 53, has become the focus of the Malaysian police inquiry after investigators conducted more than 170 interviews, according to the Sunday Times.

Of all the other 279 passengers and crew members on board the flight to Beijing via Kuala Lumpur, Shah is the only one to raise suspicion following intelligence checks.

Data from a flight simulator seized by police at his Kuala Lumpur home shortly after the plane vanished on 7 March contains evidence of rehearsed flight drills out into the southern Indian Ocean and a landing on an island with a short runway.

These files had been deleted but computer experts have now retrieved them.

The initial results of the probe have not been published but have been shared with foreign governments and investigators. They have been disclosed by people in the aviation industry and government officials in southeast Asia.

It does not rule out other explanations – such as an act of terrorism or mechanical failure – as the cause of one of the greatest mysteries in aviation history.

A spokesman for the Malaysian Police said: "The police investigation is still ongoing. To date no conclusions can be made as to the contributor to the incident and it would be sub judice to say so. Nevertheless, the police are still looking into all possible angles."

When asked about the simulator, the spokesman added: "The leads uncovered so far are still being investigated."

Malaysia's prime minister, Najib Razak, hinted the government's suspicions of "deliberate action by someone on the plane", on 15 March.

Background checks on Shah revealed he had no social or work commitments planned for the future, unlike his co-pilot, Fariq Hamid, and the rest of the crew. There have also been rumours - described as "lies" by his family - concerning Shah's failed marriage with wife Faizah Khan, and a close friend told The New Zealand Herald that Shah was in "no state of mind to be flying".

Meanwhile, the search for the missing aircraft will shift its focus to a new area of the Indian Ocean at the end of the month.