Malaysian police have searched the homes of the pilots of the Malaysia Airlines plane that vanished eight days ago with 239 people on board.
The police are also reportedly looking at the family life and psychological state of pilot Zaharie Ahmad Shah, 53, and co-pilot Fariq Abdul Hamid, 27.
This comes after the authorities said the communications systems of the plane had been deliberately disabled.
According to satellite evidence, the Boeing 777 could have continued flying for a further seven hours after its last radar contact, Malaysian Prime Minister Najib Razak said.
He added that the plane could be anywhere from Kazakhstan to the Indian Ocean.
Mr Razak stopped short of saying it was a hijacking, saying only that they were investigating "all possibilities".
In a separate development, India on Sunday suspended its search for the plane around the remote Andaman and Nicobar Islands and also in the Bay of Bengal. Delhi said it acted at the request of the Malaysian authorities.
China - which had 153 citizens on board flight MH370 - has urged Malaysia to continue providing it with "thorough and exact information" on the search.
The Kuala Lumpur homes of Mr Zaharie and Mr Fariq were searched on Saturday, and the authorities have so far released few new details on the pilots' investigation.
Mr Zaharie joined Malaysia Airlines more than 30 years ago, and was considered a very experienced pilot.
Mr Fariq recently recently graduated to the cockpit of a Boeing 777. It is believed that he was considering marriage.
Plane's systems 'deliberately disabled'
The Malaysian prime minister told a news conference that new satellite evidence shows "with a high degree of certainty" that one of the aircraft's communications systems - the Aircraft and Communications Addressing and Reporting System (ACARS) - was disabled just before it had reached the east coast of Malaysia.
ACARS allows computers aboard the plane to "talk" to computers on the ground, relaying in-flight information about the health of its systems.
The BBC reports that investigators will now focus on trying to obtain the radar data from any of the countries the Boeing 777 may have passed over.
This could include Thailand, Myanmar, Nepal, Bangladesh, Bhutan, China, India and Pakistan.
Mr Najib said that in light of the new evidence, the investigation had "entered a new phase" and would focus on the crew and passengers on board.
Agonising wait continues
The families of those on board the flight have endured an agonising wait for news since the plane disappeared on 8 March.
An extensive search of the seas around Malaysia - involving 14 countries, 43 ships and 58 aircraft - has proved fruitless.
The Boeing 777 has one of the best safety records of any jet, and authorities have struggled to find any indication of what went wrong, keeping alive a host of theories that include a mid-air explosion, terrorist act, catastrophic technical failure or rogue missile strike.
- 153 Chinese including a delegation of artists
- 38 Malaysians including an official who was due to start a job at a branch office in Beijing
- 2 Iranians using false passports in a bid to seek asylum in Europe
- 3 Americans including an IBM executive who had recently relocated to Kuala Lumpur
- 2 Canadians returning to Beijing after a business trip
- 7 Indonesians, 6 Australians, 5 Indians and 4 French
- 2 each from New Zealand and Ukraine
- one each from Russia, Taiwan and Netherlands.
The developments have added further uncertainty to the relatives of the 239 people on board the Kuala Lumpur to Beijing flight.