U.S. intelligence officials are leaning toward the theory that "those in the cockpit" -- the pilots of Malaysia Airlines Flight 370 -- were responsible for the mysterious disappearance of the commercial jetliner, a U.S. official with direct knowledge of the latest thinking told CNN on Saturday.
The revelation followed news that Malaysian authorities searched the home of the lead pilot, a move that came the same day that Prime Minister Najib Razak told reporters the plane veered off course due to apparent deliberate action taken by somebody on board.
The Malaysian government had been looking for a reason to search the home of the pilot and the co-pilot for several days. But it was only in the last 24 to 36 hours, when radar and satellite data came to light, that authorities believed they had sufficient reason to go through the residences, according to the U.S. official, who spoke on condition of anonymity.
"The Malaysians don't do this lightly," the official said. It's not clear whether the Malaysian government believes one or both the men could be responsible for what happened when the Boeing 777-200 ER disappeared March 8 en route from Kuala Lumpur to Beijing.
What we know about the cockpit crew
The official emphasized no final conclusions have been drawn and all the internal intelligence discussions are based on preliminary assessments of what is known to date.
Other scenarios could still emerge. The notion of a hijacking has not been ruled out, the official said.
A source close to the investigation told CNN that Malaysian police had searched the home of pilot Zaharie Ahmad Shah, 53. Shah lives in an upscale gated community in Shah Alam, outside Malaysia's capital of Kuala Lumpur.
Two vans were loaded with small bags, similar to shopping bags, at the home of the co-pilot, 27-year-old Farq Ab Hamid, according to a CNN crew who observed activities at the residence. It was unclear whether the bags were taken from the home, and police made no comment about their activities there.
Najib made clear in a press conference that in light of the latest developments, authorities have refocused their investigation to the crew and passengers on board.
Undoubtedly, they will scour through the flight manifest and look further to see whether any of the passengers on board had flight training or connections to terror groups.
A senior U.S. law enforcement official told CNN that investigators are carefully reviewing the information so far collected on the pilots to determine whether there is something to indicate a plan or a motive.
That would seem supported by preliminary U.S. intelligence reports, which the U.S. official said show the jetliner was in some form of controlled flight at a relatively stable altitude and path when it changed course and flew toward the Indian Ocean. It is presumed by U.S. officials to have crashed, perhaps after running out of fuel.
'Someone acting deliberately'
The first clue that perhaps one or both of the pilots were involved stem from when the plane made a sharp, deliberate turn from where it last communicated with Kuala Lumpur air traffic controllers, and before it would have to communicate with Vietnamese controllers, according to the U.S. official with knowledge of the latest intelligence thinking.
"This is the perfect place to start to disappear," the official said.
Military radar showed the jetliner flew in a westerly direction back over the Malaysian peninsula, Najib said. It is then believed to have either turned northwest toward the Bay of Bengal or southwest elsewhere in the Indian Ocean, he said.
"Evidence is consistent with someone acting deliberately from inside the plane," the Prime Minister said, officially confirming the plane's disappearance was not caused by an accident. "....Despite media reports that the plane was hijacked, we are investigating all major possibilities on what caused MH370 to deviate."
The focus of the search is now in the southern Indian Ocean. "The southern scenario seems more plausible," the official said.
Meanwhile, according to Najib, new satellite information leads authorities to be fairly certain that someone disabled the Aircraft Communications Addressing and Reporting System, or ACARS, just before the aircraft reached the east coast of peninsular Malaysia.
"Shortly afterward, near the border between Malaysian and Vietnamese air traffic control," Najib said, "the aircraft's transponder was switched off."
ACARS is the system that routinely transmits information like turbulence and fuel load back to the airline. A transponder is a system controlled from the cockpit that transmits data about the plane via radio signals to air traffic controllers. It combines with ground radar to provide air traffic controllers with details about the plane, including its identification, speed, position and altitude.
The last voice communication from the cockpit a week ago were these words: "All right, good night."