MH370 investigation: Malaysia narrows criminal probe to cabin crew of missing flight

Kuala Lumpur: Malaysia is focusing its criminal investigation on the cabin crew and pilots of a missing Malaysia Airlines plane, after clearing all 227 passengers of any involvement, the country's police chief was reported as saying on Wednesday.

National police chief Khalid Abu Bakar said the passengers had been cleared of possible involvement in hijacking, sabotage or having personal or psychological problems that could have been connected to the flight's disappearance on March 8.

"They have been cleared of the four," he was quoted as saying by state news agency Bernama.

Khalid could not be reached by Reuters for comment and the country's home minister declined to confirm the report.

Malaysian authorities have still not ruled out mechanical problems as causing the disappearance, but say evidence suggests the plane was deliberately diverted from its scheduled route from Kuala Lumpur to Beijing.

Investigators believe that someone with detailed knowledge of both the Boeing 777-200ER and commercial aviation navigation switched off the plane's communications systems before diverting it thousands of miles off its scheduled course.

That has turned the focus of investigations onto the two pilots, 53-year-old captain Zaharie Ahmad Shah and his co-pilot, 27-year old Fariq Abdul Hamid.

But the police say their investigation into the men has failed to turn up any red flags. The FBI helped Malaysian authorities analyse data from Zaharie's personal flight simulator but found nothing suspicious.

Search teams in the southern Indian Ocean are in a race against time to locate the plane's black box recorder, which has an expected battery life of around 30 days and may well contain the key to understanding the plane's mysterious disappearance.

"We are focusing on the pilots but we can't get much clarity until we have the black box," one senior police source told Reuters.