Malaysian authorities have said that evidence so far suggests the plane was deliberately turned back across Malaysia to the Strait of Malacca, with its communications systems disabled. They are unsure what happened next.
Earlier Monday, Malaysia’s police chief, Inspector General Khalid Abu Bakar, reiterated that all the passengers had been cleared of suspicion. But he said the pilots and crew were still being investigated and declined to comment on whether officials had recovered files that were deleted a month earlier from the home flight simulator of the chief pilot.
Officials have said the plane automatically sent a brief signal — a “ping” — every hour to a satellite belonging to Inmarsat, a British company, even after other communication systems on the jetliner shut down.
The pings did not include any location information, but an initial analysis showed that the location of the last ping was probably along one of two vast arcs running north and south.
Najib said Inmarsat did further calculations “using a type of analysis never before used in an investigation of this sort,” and had concluded that the plane’s last position was “in the middle of the Indian Ocean, west of Perth.”
He gave no indication of exactly where in the Indian Ocean the plane was last heard from, but searchers have sighted possible debris in an area about 2,000 kilometers (1,240 miles) southwest of Perth, and Najib said more details would be released Tuesday.
Search teams from 26 nations have pored over radar data and scoured a wide swath of Asia for weeks with advanced aircraft and ships, but no confirmed wreckage has been found.
The hunt is now considered a race against time because of the battery life of the “pinger” in the black box is running out and may have less than two weeks left.
On Monday, an Australian navy support vessel, the Ocean Shield, headed toward the search zone and was expected to arrive in three or four days, a defense official said. The ship is equipped with acoustic detection equipment that can search for the black box.