(CNN) — The investigation into the disappearance of Malaysia Airlines Flight 370 shifted Saturday to the passengers and crew after data showed the plane deviated from its flight plan due to what appears to be deliberate action, Prime Minister Najib Razak said Saturday.
“Malaysian authorities have refocused their investigation on crew and passengers aboard,” Najib told reporters. “Evidence is consistent with someone acting deliberately from inside the plane.”
Najib stopped short of calling it a hijacking, saying investigators have not made a final determination.
“Despite media reports that the plane was hijacked, we are investigating all major possibilities on what caused MH370 to deviate,” he said.
Shortly after he spoke, a source close to the investigation told CNN that Malaysian police had searched the home of pilot Zaharie Ahmad Shah, 53. Shah lives in a gated community in Shah Alam, outside Kuala Lumpur.
Earlier Saturday there was no police presence at the residence of his co-pilot, Fariq Ab Hamid, 27.
Kazakhstan to Indian Ocean
As the focus of the investigation has shifted, so too has the focus of the search. “The plane’s last communication with the satellite was in one of two possible corridors: a northern corridor stretching approximately from the border of Kazakhstan and Turkmenistan to northern Thailand, or a southern corridor stretching approximately from Indonesia to the southern Indian Ocean,” Najib said.
Given that the new search area involves a number of countries, the relevant foreign embassies have been given access to the new information. Malaysia’s Foreign Ministry will brief the governments that had passengers aboard the plane and will brief the relatives of its 239 passengers and crew.
The passenger jetliner disappeared on March 8, en route from Kuala Lumpur to Beijing.
“Based on new satellite information, we can say with a high degree of certainty that the Aircraft Communications Addressing and Reporting System, or ACARS, was disabled just before the aircraft reached the East Coast of peninsular Malaysia,” the Prime Minister said. “Shortly afterward, near the border between Malaysian and Vietnamese air traffic control, the aircraft’s transponder was switched off. From this point onwards, the Royal Malaysian Air Force primary radar showed that an aircraft — which was believed but not confirmed to be MH370 — did turn back.”
Military radar showed the jetliner flew in a westerly direction back over the peninsula before turning northwest toward the Bay of Bengal or southwest into the Indian Ocean, he said.
“Up until the point at which it left military primary radar coverage, these movements are consistent with deliberate action by someone on the plane,” he said, adding that investigators had confirmed by looking at the raw satellite data that the plane in question was the Malaysia Airlines jet.
The same conclusion was reached by the U.S. Federal Aviation Administration, the U.S. National Transportation Safety Board, the British Air Accidents Investigation Branch and the Malaysian authorities, all of whom were working separately with the same data, he said.
Air traffic controllers outside Kuala Lumpur said they lost contact with the plane on March 8 at 1:30 a.m. local time, about 45 minutes after takeoff. The Prime Minister said its last communication with a satellite was at 8:11 a.m. the same day, but its precise location was unclear.
Najib noted that theories and conspiracy theories on what happened abound.
“There has been intense speculation,” Najib said. “We understand the desperate need for information on behalf of the families and those watching around the world. But we have a responsibility to the investigation and the families to only release information that has been corroborated.”
Hours before Najib’s announcement, U.S. officials told CNN the flight had made drastic changes in altitude and direction after disappearing from civilian radar.
The more U.S. officials learn about the flight, “the more difficult to write off” the idea that some type of human intervention was involved, an official familiar with the investigation said.
CNN has learned that a classified analysis of electronic and satellite data suggests the flight may have crashed in the Bay of Bengal or elsewhere in the Indian Ocean.
Taken together, the data point toward a possible scenario in which someone may have taken control of the plane for some unknown purpose.
The jetliner was flying “a strange path,” a U.S. official said on condition of anonymity. The details of the radar readings were first reported by The New York Times on Friday.
Malaysian military radar showed the plane climbing to 45,000 feet — which is above its approved altitude limit — soon after disappearing from civilian radar screens and then dropping to 23,000 feet before climbing again, the official said.
Fourteen countries, 43 ships and 58 aircraft are involved in the search, the Prime Minister said.
Shortly after Najib delivered his remarks, China demanded that Malaysia provide more information on the investigation. China is sending technical experts to join the investigation.
Most of the passengers aboard were Chinese.
CNN’s Tom Watkins, Saima Mohsin, Chelsea J. Carter and Yuli Yang contributed to this report.
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