Malaysia's Transport Minister Hishamuddin Hussein told the press Sunday that someone shut down the Aircraft Communications Addressing and Reporting System on the missing Malaysia Airlines flight before the pilot's last words over radio.

"We have to hand you over to Ho Chi Minh city," Air Traffic Control told the pilot.

"All right, good night," the pilot said back in his last transmission.

(Update 3/17: Malaysia Airlines has said it is unclear when the ACARs system was shut down.)

Malaysia's investigation has shifted to a criminal inquiry following the country's announcement on Friday that attempts to turn off communications equipment and divert the aircraft were "deliberate action by someone on the plane."

On Saturday, police visited the homes of the pilot and the co-pilot. They are also reportedly examining a flight simulator that one of the pilots, Captain Zaharie Ahmad Shah, kept at home.

Shah, 53, is reportedly a supporter of Malaysia's opposition leader, Anwar Ibrahim, who was jailed for sodomy (i.e., homosexuality) only hours before the flight vanished. Shah reportedly attended the controversial trial.

Both pilots are known to be community-mind family men. Neither has been connected to any wrongdoing.

An American businessman who has traveled with Malaysia Airlines regularly told The Washington Times that pilots did not always keep the cockpit door locked during flights.

The man, a former pilot who rides first class as he conducts aviation sales in the region, said that he even tried the door one time on the way back from the bathroom and found it unlocked.

“From personal experience, it would seem to be easy for someone with half a plan to enter the cockpit and take control," he said.

Officials said that Malaysia Airlines Flight 737, which has been missing for more than a week, had not been loaded with any extra fuel and that the pilot and co-pilot did not ask to fly together, according to Channel News Asia's Sumisha Naidu.

With the exception of the transponder, which can be shut off at the flick of a switch, other onboard tracking systems are not as easy to disable, leading investigators to believe whoever turned off tracking systems had intimate knowledge of them, a number of commercial pilots told NPR on Friday.

The captain and first officer of the plane were both experienced pilots. Capt. Shah, 53, began with the airline in 1981 and had logged 18,365 flying hours, while First Officer Fariq Ab. Hamid, 27, joined in 2007 and had 2,763 hours logged.

Authorities may also be looking at an aviation engineer who was among the passengers, The New York Times reports.

The search effort greatly expanded Friday, as the Malaysian P.M. introduced two massive new search "corridors" — a northern corridor stretching from northern Thailand to the border of Kazakhstan and Turkmenistan, and a southern corridor stretching from Indonesia to the southern Indian Ocean.



"Clearly the search for MH370 has entered a new phase," Razak said Friday. "We hope this new information brings us one step closer to finding the plane."

If the plane crashed in the Indian Ocean, it could be nearly impossible to find, given the ocean's depth and lack of radar coverage.



Malaysian authorities are currently asking for any further information from nearly a dozen Asian countries that the missing jetliner may have flown over.