Missing Malaysia Airlines flight MH370 and probe on pilots
A relative of a passenger onboard Malaysia Airlines Flight MH370 prays in front of a placard reading "We need the truth" at a praying room at Lido Hotel, in BeijingReuters

All the 227 passengers aboard the missing Malaysia Airlines flight MH370 have been "cleared" of any motive to hijack or sabotage the plane, and of having any psychological and personal problems, following a thorough probe while further investigation focuses on the remaining 12 crew members, Malaysian authorities say.

Malaysia's Inspector General of Police Khalid Abu Bakar has said the investigators continue to probe the cabin crew members, including the pilot and the co-pilot, to look for any foul play.

"They [passengers] have been cleared of the four [elements]. It [is] according to our own procedure [investigation]," Abu Bakar told reporters.

All the 12 crew members of the aircraft were Malaysian nationals.

The Boeing 777 passenger aircraft, with 239 people on board, went missing on 8 March en route to Beijing. Neither the jetliner nor its debris has been found so far although authorities now believe the airliner crashed in the southern Indian Ocean.

The Malaysian police have said they have recorded over 170 statements from individuals and are likely to question many more pertaining to the mysterious disappearance of the jet.

However, the police chief refused to divulge more information on the ongoing investigation which has been narrowed down to the crew.

"I'm sorry, there are things we cannot reveal to you; not that I don't want to reveal to you but we cannot do that. Because it's a criminal investigation, ongoing; we have not concluded the whole thing and we are still awaiting reports from experts overseas and internally."

"You must understand that. I think we have been very consistent [during the probe]. Who knows, maybe there will be prosecution later on. So, this will affect the prosecution's case if we start revealing our findings."