Diane? Well, bob, as you say, as the M mistery deepens. And correspondent Brian Ross spent the day tracking down new details. Reporter: The captain, 53-year-old zaharie Ahmad shah, was a pilot's... See More
Diane? Well, bob, as you say, as the M mistery deepens. And correspondent Brian Ross spent the day tracking down new details. Reporter: The captain, 53-year-old zaharie Ahmad shah, was a pilot's pilot. Seen here on his own youtube channel, at the controls of a flight simulator. This is a youtube video I've made as a community service. Reporter: The 35-year veteran of the airline, with more than 18,000 hours of flying. His co-pilot, 27-year-old fariq Abdul Hamid is much less experienced. And today, the airline said it was investigating troubling reports he was kind of an airborne playboy, violating safety standards in the cockpit. According to an Australian news report, these two, young women were invited by the co-pilot to ride with him in the cockpit on a 2011 flight from Kuala lampur. At one stage, they were pretty much turned around in their seats talking to us. And they were so engaged in conversation. Reporter: Still, there's nothing known about the background of the two Malaysia air pilots that suggest foul play. But backgrounds of the pilots are coming into sharp focus with new reports the plane veered far off course for an hour, after turning off its transponder tracking signal, raising questions, today, of possible hijacking or even pilot suicide. You cannot discount any theory. Who had the ability to turn off the transponder? I don't know. Reporter: It was just last month that the co-pilot of an ethiopian airliner hijacked his own flight to Switzerland. In 1999, authorities ruled that the pilot of an Egypt air passenger jet flew the plane into the ocean, after takeoff from Kennedy airport in New York. And pilot error has been tied to the mysterious crash of an air France flight into the atlantic. But investigators found the pilots flew into dangerous weather and failed to take proper action after developing a mechanical problem. U.s. Authorities tell ABC news, tonight, that the homes of the two Malaysia air pilots have now been searched, looking for any clues that might answer the mystery, Diane, of why and how this plane disappeared. All right, Brian Ross. Thanks to you. Brian and bob continuing our coverage throughout this night.
This transcript has been automatically generated and may not be 100% accurate.