The mystery of the disappearance of a Malaysian passenger jet deepened Monday, with investigators concluding that oil slicks found off the coast of Vietnam are not connected to the aircraft.
Officials in Kuala Lumpur say a laboratory analysis showed that the streaks of oil found in the Gulf of Thailand were of a type of fuel used by ships.
Malaysian officials say there is still no sign of the missing passenger plane nearly three days after it disappeared with 239 people on board. One investigator said searchers have found nothing that appears to be from the Boeing 777, despite some reports of debris floating in waters south of Vietnam.
"We have not found anything that appears to be object from the aircraft, let alone the aircraft."
The plane, Flight MH370, disappeared from radar Saturday morning about an hour after it took off from Kuala Lumpur en route to Beijing.
Officials say they are no closer to finding out what might have happened to the aircraft, and have not ruled out anything, including hijacking or a mid-air disaster. About two-thirds of the people on board were Chinese nationals, with the remainder from other Asian countries, Europe and North America.
Investigators from eight countries, including the United States, have been searching for the missing plane and investigating two passengers who boarded the aircraft with stolen Italian and Austrian passports.
On Sunday, officials investigating the disappearance of the Malaysia Airlines flight said radar images show the missing jet may have inexplicably turned back before vanishing.
Also Sunday, Thai police said they were investigating a "passport ring" as details emerged of bookings for the flight made in Thailand with stolen European passports.
Two Europeans were listed on the passenger manifest, but neither man boarded the plane.
Both had their passports stolen in Thailand within the past two years. Malaysia is investigating the suspect passengers and the United States has sent in the Federal Bureau of Investigation to assist.
The Malaysia Airlines flight disappeared from radar screens after taking off from Kuala Lumpur in good weather. Air traffic controllers say they did not receive a distress call before the jet disappeared.
The Boeing 777 is a very popular plane with an excellent safety record. The most recent accident involving a Boeing 777 was the Asiana Airlines crash at San Francisco International Airport in July 2013. Three people were killed. Pilot error is suspected in that incident.