KUALA LUMPUR, Malaysia (AP) -- The mystery surrounding the fate of Malaysian Airlines Flight 370 only deepens with each new bit of information that emerges.
Authorities say the final words from the cockpit came after one of the plane's communications systems had been disabled, but gave no indication anything was wrong. Now investigators are trying to determine who spoke those words, whether one or both pilots were involved in the plane's disappearance and, if so, whether they acted under duress.
About 14 minutes after the first communications system was disabled, the transponder, which identifies the plane to commercial radar systems, was also shut down.
But the first system, which transmits information about the plane's engines and other parts to the airline, continued to send faint hourly pulses that were recorded by a satellite. The last "ping" was sent seven hours and 31 minutes after the plane took off. That greatly expands the territory searchers have to cover.
Malaysian officials are asking other governments to share sensitive radar data. They say without it, locating the plane might be impossible.
Investigators are also using satellite data in an effort to track the flight of the plane. Despite most of its navigation systems and other devices being turned off, the plane sent out signals once every hour while it was in flight. Such data has not been used before in tracking aircraft, but it may be the only remaining method of finding the aircraft.
Investigators are looking into the background of all 239 people on the flight and the ground crew that serviced the plane. They're also examining a flight simulator taken from the home of one of the pilots.
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