But U.S. officials maintained Thursday afternoon that the information from the airplane's data system was being actively pursued in the plane investigation.
Analysts from U.S. intelligence, the Federal Aviation Administration and the National Transportation Safety Board have concluded that the pings likely came from the missing aircraft, the senior U.S. official said.

There is reason to believe the plane flew for four hours, officials said, but there is no specific indication where the plane actually is.
Multiple bursts of data were received indicating the plane was flying over the Indian Ocean, the senior U.S. official told CNN.

But there's another confusing twist. An emergency beacon that would have sent data upon impact apparently did not go off, the official said. The beacons, known as Emergency Locator Transmitters, activate automatically upon immersion in fresh or salt water, but must remain on the surface for a distress signal to transmit.

The failure of the beacon to activate could mean that the plane didn't crash, that the transmitter malfunctioned, or that it's underwater somewhere.