stunning new developments on the missing jumbo jet. First reported by ABC news, someone who knew what they were doing turned off two key tracking devices in the cockpit. One at 1:07 A.M. The other at... See More
stunning new developments on the missing jumbo jet. First reported by ABC news, someone who knew what they were doing turned off two key tracking devices in the cockpit. One at 1:07 A.M. The other at 1:21 A.M. That's a 14-minute gap cutting off contact with the plane and what this gap suggests there was no catastrophic failure, it was a deliberate act done by someone taking over the plane. What it also says those extra four hours after that last contact mean that the plane could have flown anywhere for thousands of miles. This American ship now leading a search in the Indian ocean west of Malaysia. David Kerley is here today with all this brand-new information. Good morning, David. Reporter: This is a massive expansion of the search area. If you look at the map, four hours and 600 miles an hour you're talking about a 2400-mile area that now could be considered part of the search zone. But we have also learned from U.S. Sources they believe some of the communication systems as you mentioned were intentionally turned off at different times meaning this was not a catastrophic failure. ABC news has learned that those two separate key moves in the cockpit may be crucial to solving the mystery. Just 26 minutes into the flight at 1:07 A.M. The final data transmission was made from the cockpit at some point that system shut down. 14 minutes later at 1:21 the transponder which sends the location of the 777 also turned off. One source told us it was a systematic shutdown. The assumption, that someone with flying experience didn't want this jet to communicate with the outside world. Our sources tell us one feature that apparently cannot be manually turned off is a ping feature which is part of a data health system for the aircraft. If the plane had disintegrated during night or suffered a failure it's expected all three signals, the pings, the data messages and transponder would stop at the same time. In the case of Malaysia air flight the ping continues hourly our sources say for four hours after the flight disappeared off radar. That ping may not tell us where the plane actually is but at 600 miles an hour it could be 2400 miles from Malaysia, which is why the investigation is expanding into the Indian ocean this morning with U.S. Vessels moving in that direction. And, George, this is a very big ocean and even deeper than some of the places that we found the wreckage from the air France accident several years ago. And we should emphasize right now this idea that it was a deliberate act potentially sabotage, the leading theory but not the only theory. Absolutely. This is a possibility that there was a fire. Could have been cargo problems, could be that the pilots were lack of oxygen had hypoxia and passed out. This is the leading theory. This is what the Americans have found out so far and now we're talking about this entire part of the Indian ocean which as I mentioned is very deep. They think that that flight path that they got one ping over here kind of leads them over into this area and into the Indian ocean.
This transcript has been automatically generated and may not be 100% accurate.