Police officers visited the houses of pilots of the missing Malaysia Airlines plane on Saturday, as the investigation over the jetliner's whereabouts changed focus following a revelation it was deliberately diverted and continued flying for more than six hours after losing contact with the ground.
Malaysian Prime Minister Najib Razak confirmed after days of mounting speculation that the disappearance of the MH370 flight to Beijing more than a week ago was not accidental.
It refocused the investigation into the flight's crew and passengers, and underlined the massive task for searchers who already have been scouring vast areas of ocean.
Investigators were looking into all possibilities as to why the Boeing 777 deviated so drastically from its original flight path, saying authorities could not confirm whether it was a hijacking.
Earlier on Saturday, a Malaysian official had said the plane was hijacked, though he added that no motive had been established and no demands had been made known.
Pilots Zaharie Ahmad Shah, 53, and Fariq Abdul Hamid were described as respectable, community-minded men.
Zaharie joined Malaysia Airlines in 1981 and had more than 18,000 hours of experience.
His Facebook page showed an aviation enthusiast who flew remote-controlled aircraft, posting pictures of his collection, which included a lightweight twin-engine helicopter and an amphibious aircraft.
Fariq was contemplating marriage after having just graduated to the cockpit of a Boeing 777.
He has drawn scrutiny after the revelation that in 2011, he and another pilot invited two women aboard their aircraft to sit in the cockpit for a flight from Phuket, Thailand, to Kuala Lumpur.
Fourteen countries are involved in the search, which is using 43 ships and 58 aircraft.
The plane was carrying 239 people when it departed for an overnight flight from Kuala Lumpur to Beijing at 12:40am (local time, 16:30 GMT) on 8 March.
Its communications with civilian air controllers were severed at about 1:20am (local time, 17:20 GMT) and the jet went missing - heralding one of the most puzzling mysteries in modern aviation history.