This post is being updated throughout the day Sunday.
After a second day of frantic searching failed to uncover the fate of Malaysia Airlines flight MH370, ships and aircraft are combing over parts of the Gulf of Thailand and South China Sea where the jetliner is suspected of crashing with 239 people aboard.
Vietnamese officials say search planes have spotted an object that could be debris from the jet — but darkness fell in Asia hours ago, complicating any attempts to verify or expand on that claim.
The flight's disappearance is a mystery that was deepened by revelations that two passports used by passengers on the flight had been listed as stolen or lost, according to Interpol. And on Sunday, Malaysian transportation and military officials said radar data seemed to indicate a change of course just before contact with the plane was lost.
As can happen when news is breaking, some information that's being reported may later turn out to have been incorrect. We'll focus on reports from officials involved in the search and news outlets that have reporters in important locations.
Update at 11:50 a.m. ET: Object Spotted In Water Near Vietnam
A Vietnamese military aircraft has spotted an object in the sea that could be from the missing Boeing 770, officials of Vietnam's government said late Sunday, local time. News of the potential discovery comes after more than 36 hours of uncertainty for friends and family members of the passengers on the flight.
But it's important to remember that the object might not be related to the Malaysian flight. Oil slicks were spotted on the water Saturday, for instance; they didn't reveal the plane's whereabouts. And as Reuters reminds us, "Malaysian officials had earlier said no wreckage had yet been found, despite a search involving 34 aircraft and 40 ships."
The Civil Aviation Authority of Vietnam announced the sighting at a news conference Sunday, releasing a photograph taken from a search plane. The agency says it's forming a forward headquarters in the area of the discovery.
It's currently nighttime in the area, complicating efforts to officially confirm the sighting. The search for the missing jetliner continues, with several aircraft detailed to examine the area where the potential debris was spotted, Vietnamese officials said late Sunday.
The rules and procedures for an international rescue and salvage operation are complicated.
As explained by the National Transportation Safety Board, deciding which country heads the investigation depends on where the discovery is made. Such decisions follow protocols established by the International Civil Aviation Organization.
From the coordinates provided by Vietnamese officials Sunday, the objects spotted in the water would seem to be (by our own unofficial estimate) about 100 miles west of Vietnam's southern coast, southwest of the island of Tho Chu in the Gulf of Thailand.
Update at 9 a.m. ET: Interpol Says Passports Were Listed As Stolen
Interpol confirms that "at least two passports" used to board flight MH370 were listed in its Stolen and Lost Travel Documents database. And matching up with what's been reported, the agency identified them as being Austrian and Italian documents.
Saying that "it is too soon to speculate about any connection between these stolen passports and the missing plane," Interpol Secretary General Ronald K. Noble adds that "it is clearly of great concern that any passenger was able to board an international flight using a stolen passport listed in Interpol's databases."
The agency says it's also reviewing other passports used to board the flight.
Our original post continues:
The most recent inspection of the Boeing 777-200 was performed 10 days ago and didn't turn up any problems, Malaysia Airlines officials say. And from all accounts, the weather during the flight isn't seen as being a problem, either.
There have been hints that a discovery of the plane might be imminent, from a reported sighting of twin oil slicks by Vietnamese military search planes Saturday to a photograph circulating on social media in China Sunday that purports to be debris from the jet seen from the window of another Malaysia Airlines flight traveling from Beijing to Kuala Lampur — the opposite route of the missing flight. But an official sighting has not confirmed the plane's location.
"We are trying to make sense of this," Malaysian Air Force Chief Rodzali Daud told a news conference today, according to the AP. "The military radar indicated that the aircraft may have made a turn back and in some parts, this was corroborated by civilian radar."
If the flight did diverge from its planned route, the pilots would have informed air traffic controllers, said Malaysia Airlines Chief Executive Ahmad Jauhari Yahya.
"From what we have, there was no such distress signal or distress call per say, so we are equally puzzled," he said.
More than half of the flight's passengers were Chinese citizens. Many of their loved ones have gathered at a hotel in Beijing, awaiting word of the jetliner's fate and preparing themselves for the worst. They have grown increasingly frustrated with the lack of news. And on Sunday, they released a joint statement to media, calling for answers from the airline and government officials.
U.S. agencies are moving to help with the search and investigation, with the FBI and the National Transportation Safety Board saying they're sending experts to offer their assistance. As explained by the NTSB, international protocols will determine who leads the investigation once the plane is located.
Officials caution that it's far too early to speculate on a possible cause for the flight's troubles. That didn't stop speculation about a possible terrorist plot, fueled by news that two men — an Italian and an Austrian — who had initially been listed on the flight were in fact alive and well. Their passports had been stolen in Thailand in recent years, as we reported yesterday.
And Sunday, several media outlets report that the two people who used those passports got their tickets at the same time.
"The tickets were bought from China Southern Airlines in Thai baht at identical prices, according to China's official e-ticket verification system Travelsky. The ticket numbers are contiguous, which indicates the tickets were issued together."
The network goes on to say that the tickets secured travel from Kuala Lumpur to Beijing, "and then onward to Amsterdam. The Italian passport's ticket continues to Copenhagen, the Austrian's to Frankfurt."
Investigators are reviewing surveillance camera footage to learn more about the two passengers. But travelers using a stolen passport isn't as unusual as it might seem, The Wall Street Journal reports:
"A European security official said it wasn't uncommon for passengers to board flights using stolen passports. In addition, Beijing has emerged as a bustling transit hub in recent years, providing connecting flights to Europe and elsewhere from other parts of Asia, buoyed in part by a 72-hour visa-on-arrival program."
More details are emerging about the passengers, including the news that 20 employees of Freescale Semiconductor, a company based in Austin, Texas, were on board. The company says 12 of its workers who were on the plane are from Malaysia; 8 are from China.
And 29 people were returning home to China after participating in an art exhibit in Malaysia — 19 artists, along with family and staff members, according to the South China Morning Post.