Yet another theory is taking shape about what might have happened to missing Malaysia Airlines Flight 370: Maybe it landed in a remote Indian Ocean island chain.
The suggestion -- and it's only that at this point -- is based on analysis of radar data revealed Friday by Reuters suggesting that the plane wasn't just blindly flying northwest from Malaysia.
Reuters, citing unidentified sources familiar with the investigation, reported that whoever was piloting the vanished jet was following navigational waypoints that would have taken the plane over the Andaman Islands.
The radar data doesn't show the plane over the Andaman Islands, but only on a known route that would take it there, Reuters cited its sources as saying.
The theory builds on earlier revelations by U.S. officials that an automated reporting system on the airliner was pinging satellites for hours after its last reported contact with air traffic controllers. That makes some investigators think the plane flew on for hours before truly disappearing.
Aviation experts say it's possible, if highly unlikely, that someone could have hijacked and landed the giant Boeing 777 undetected.
But Denis Giles, editor of the Andaman Chronicle newspaper, says there's just nowhere to land such a big plane in his archipelago without attracting notice.
Indian authorities own the only four airstrips in the region, he said.
"There is no chance, no such chance, that any aircraft of this size can come towards Andaman and Nicobar islands and land," he said.
The Malaysian government said Friday it can't confirm the report.
And a senior U.S. official on Thursday offered a conflicting account, telling CNN that "there is probably a significant likelihood" the plane is on the bottom of the Indian Ocean.
Regardless, India has deployed assets from its navy, coast guard and air force to the south Andaman Sea to take part in a search for Flight 370, the country's Ministry of Defense said Friday. The Indian navy is leading the operation, and its Maritime Operations Center in New Delhi is coordinating the effort, the ministry said.
Indian search teams are combing large areas of the archipelago. Two aircraft are searching land and coastal areas of the island chain from north to south, an Indian military spokesman said Friday, and two coast guard ships have been diverted to search along the islands' east coast.
The jetliner, with 239 people on board, disappeared nearly a week ago as it flew between Kuala Lumpur, Malaysia, and Beijing. The flight has turned into one of the biggest mysteries in aviation history, befuddling industry experts and government officials. Authorities still don't know where the plane is or what caused it to vanish.
Suggestions of what happened have ranged from a catastrophic explosion to hijacking to pilot suicide.
Malaysian officials, who are coordinating the search, said Friday that the hunt for the plane was spreading deeper into both the Indian Ocean and the South China Sea.
"A normal investigation becomes narrower with time, I understand, as new information focuses the search," said Hishammuddin Hussein, the minister in charge of defense and transportation. "But this is not a normal investigation. In this case, the information we have forces us to look further and further afield."
On Friday, the United States sent the destroyer USS Kidd to scout the Indian Ocean as the search expands into that body of water.
"I, like most of the world, really have never seen anything like this," Cmdr. William Marks of the U.S. 7th Fleet told CNN of the scale of the search. "It's pretty incredible."
"It's a completely new game now," he said. "We went from a chess board to a football field."
More on the landing theory
James Kallstrom, a former FBI assistant director, said it's possible the plane could have landed, though he added that more information is needed to reach a definitive conclusion. He referred to the vast search area.
"You draw that arc and you look at countries like Pakistan, you know, and you get into your Superman novels and you see the plane landing somewhere and (people) repurposing it for some dastardly deed down the road," he told CNN's Jake Tapper on Thursday.
"I mean, that's not beyond the realm of realism. I mean, that could happen."
Even so, he acknowledged the difficulty of reaching firm conclusions with scraps of information that sometimes conflict.
"We're getting so much conflicting data," he said. "You veer one way, then you veer the other way. The investigators need some definitive, correct data."
On the seventh day of efforts to find the missing Boeing 777-200, here are the other main developments:
• Another lead: Chinese researchers say they recorded a "seafloor event" in waters around Malaysia and Vietnam about an hour
and a half after the missing plane's last known contact. The event was recorded in a nonseismic region about 116 kilometers (72 miles) northeast of the plane's last confirmed location, the University of Science and Technology of China said.
"Judging from the time and location of the two events, the seafloor event may have been caused by MH370 crashing into the sea," said a statement posted on the university's website.
• Tracking the pings: Malaysian authorities believe they have several "pings" from the airliner's service data system, known as ACARS, transmitted to satellites in the four to five hours after the last transponder signal, suggesting the plane flew to the Indian Ocean, a senior U.S. official told CNN.
That information, combined with known radar data and knowledge of fuel range, leads officials to believe the plane may have made it as far as the Indian Ocean, which is in the opposite direction of the plane's original route, from Kuala Lumpur to Beijing.
• Why the Indian Ocean? Analysts from U.S. intelligence, the Federal Aviation Administration and National Transportation Safety Board have been scouring satellite feeds and, after ascertaining no other flights' transponder data corresponded to the pings, came to the conclusion that they were likely to have come from the missing Malaysian plane, the senior U.S. official said.
Indian search teams are combing large areas of the Andaman and Nicobar islands, a remote archipelago in the northeast Indian Ocean.
• Malaysian response: In a statement Friday, Malaysia's Ministry of Transport neither confirmed nor denied the latest reports on the plane's possible path, saying that "the investigation team will not publicly release information until it has been properly verified and corroborated." The ministry said it was continuing to "work closely with the U.S. team, whose officials have been on the ground in Kuala Lumpur to help with the investigation since Sunday.
U.S. experts are using satellite systems to try to determine the possible location of the plane, Azharuddin Abdul Rahman, director general of the Malaysian Department of Civil Aviation, said at a news conference Friday.
On Thursday, Malaysia Airlines Chief Executive Ahmad Jauhari Yahya said that Rolls-Royce, the maker of the plane's engines, and Boeing had reported that they hadn't received any data transmissions from the plane after 1:07 a.m. Saturday, 14 minutes before the transponder stopped sending information. He was responding to a Wall Street Journal report suggesting the missing plane's engines continued to send data to the ground for hours after contact with the transponder was lost.