Indonesia's search and recovery agency says a sonar image appears to have found the wreckage of AirAsia Flight 8501 upside down on the floor of the Java Sea, CBS News has confirmed. It is unclear whether or not the plane has been found intact.

The development comes on the fourth day of the effort to find the remnants of the downed airliner that crashed early Sunday. The cause of the crash is still unknown and searchers are still attempting to recover the plane's black box to get an explanation of how the crash happened.

The earliest proof of the fate of AirAsia Flight 8501 emerged Tuesday from the shallow, aqua-colored waters of the Java Sea, confirming that the plane crashed with162 people aboard in an area not far from where it dropped off radar screens.

Two days after the jet vanished, searchers found began finding bodies and debristhat included a life jacket, an emergency exit door and a suitcase about 10 miles from the plane's last known coordinates.

The airliner's disappearance halfway through a two-hour flight between Surabaya, Indonesia, and Singapore triggered an international hunt for the aircraft involving dozens of planes, ships and helicopters.

Images of the debris and a bloated body shown on Indonesian television sent a spasm of anguish through the room at the Surabaya airport where relatives awaited news.

CBS News' Allen Pizzey reports that the first six bodies were recovered relatively quickly, and then searchers began reporting more and more bodies floating in the sea 100 miles from land and a mere 6 miles from where the airliner was last in contact with air traffic control. One of the bodies was that of a flight attendant identified by her trademark red uniform.

(CBS News)