Transcript for Missing Malaysia Airlines: New Clues About Flight's Disastrous Path
the mystery of flight 370 is evolving in new ways, ranging from the intriguing to the downright baffling. There are fresh clues, expanded search Zones, and allegations of deliberate misinformation. Tonight ABC's David Wright is in Australia taking us inside the investigation, exploring the latest theories and separating fact from fiction in this enigma that the whole world is watching. Reporter: Grainy footage of a routine airport security check, all over youtube today. Could this be the pilot and co-pilot of Malaysia airways 370 moments before they boarded the plane? That flight is now the focus of the biggest aviation mystery since Amelia earhart. Today nearly ten days after the Boeing 777 vanished the search area has expanded, most of it shimmering ocean. From the cockpit this ocean seems endless and it feels like an inch by inch search. Reporter: ABC's Gloria Riviera had a front row seat for ten hours of searching today, searching in vain. On the ground Perth on the west coast of Australia has become a central staging area. 26 nations are now involved in the search and rescue. You're at pierce air base. They'll be spearheading the effort as it reaches into the southern reaches of the Indian ocean. Aviation experts tell us that's the most likely place this plane ended up. But the thing is no one can say for sure. Reporter: This in an era when technology is not supposed to let things simply disappear. Least of all a jumbo jet with 239 souls on board. But so far instead of answers it's become a real-life episode of "Lost." A mystery in danger of unraveling into conspiracy theories. Could the plane have landed somewhere? Were the pilots involved? Could a catastrophic failure have incapacitated everyone on board? Here's what we do know for certain. Flight mh370 took off from Kuala Lumpur at 12:41 A.M. Bound for beijing. 1:19 the cockpit checks in with the tower one last time. "All right. Good night," he said. Today we learned that last radio transmission most likely came from this man, 27-year-old co-pilot fariq Abdul Hamid. Initial investigation indicated it's the co-pilot. Reporter: Shortly after that the plane's transponder shut off and the airliner turned sharply west, a maneuver one source tells ABC news was preprogrammed into the flight plan. The last clue came nearly seven hours later. 8:11 A.M., when a satellite over the Indian ocean picked up a ping from the missing plane, showing not its exact location but its distance from the satellite, creating this huge search area and three unanswered questions. Could flight 370 have landed? It's possible. The northern route has plenty of landing sites. But authorities say it would have been next to impossible that no one would notice. I know the concept or hope of the airplane landing somewhere keeps coming up. That seems very unlikely to me. Mainly because it's a big airplane with 200-some people on board. If it landed, what do you do with all these people. They have cell phones. They'd be communicating. Reporter: The southern route, too, has a dizzying number of air strips. All of those little red dots. Some of them on remote islands not much used since the Vietnam war. A Boeing 777 would need about 4,000 feet of runway to land. Most of these, too small. I haven't seen any land masses out there big enough to land the airplane on. Reporter: Another theory. Were the pilots involved? Over the weekend authorities searched the home of captain zaharie Ahmed shah, seizing a flight simulator they found there. The co-pilot, too, is being looked at closely, especially since it was his voice last heard from the cockpit. Sources tell ABC news there is considerable evidence of human intervention in the path the flight took. Based on the movements of the aircraft and what's been happening, a deliberate act seems more likely to me than a mechanical failure. Reporter: Finally, what about catastrophic failure? The plane out of control, on autopilot until it ran out of fuel. The pilot and the passengers somehow incapacitated, unable to stop it or call for help. The plane is monitored by flight computers that will keep the airplane in a stable state. It's protected from severe banks to keep the airplane from spiraling out of control. And these protections that are built into the airplane may very well protect a pilotless plane in a situation like this. Reporter: For the families this is not just a cliff-hanger. It is agony. It's hard because -- because we need answers. We need answers. Reporter: American James wood's brother Phil was on flight 370. Phil wood's cubicle in Kuala Lumpur now decorated with paper cranes. His brother James keeping the faith by recalling Phil's favorite quote from the bible, "Be still and know that I am god." If he's listening, Phil, I love you. And keep the faith, brother. Reporter: For now there is no answer back. Only stillness. Despite the frantic search for answers. I'm David Wright for "Nightline" in Perth. Our thanks to David Wright. And we here at ABC news will continue to cover this story.
This transcript has been automatically generated and may not be 100% accurate.