Malaysian authorities said today that oil slicks found on the waters near Vietnam, that were thought to be the leading clue as to the whereabouts of missing Malaysia Airlines Flight MH370, actually came from a ship. 

The Malaysian Insider reports that the Malaysian Maritime Enforcement Agency (MMEA) Eastern Region chief First Admiral, Datuk Nasir Adam, said that the oil slicks were not related to the plane, which has been missing since ground controllers lost contact with it shortly after takeoff on Saturday. The plane was en route from Kuala Lumpur to Beijing when it disappeared, and there's been no trace of it since.

Malaysian aviation press conference. AP Photo/Daniel Chan

Samples of the oil slick were sent for analysis in the Malaysian capital Petaling Jaya and according to Adam, "the result of the analysis is negative, the samples are not from MH370."

The Insider adds that chemists performed a series of tests on the sample, one to see if it contained "mineral oil," a second to see whether it contained "light" or "heavy" oil, and a final profiling test to see if the slick is from kerosene, diesel or petrol. MMEA Director-General Maritime Admiral Datuk Mohd Amdan Kurish said, however, that the oil was yellowish, different from oil generally spilled from ships. 

The oil slicks appeared to be the most definitive trace of the lost flight, so now investigators are left with even less of an insight into what happened to the plane. Malaysia's Civil Aviation Authority chief, Azharuddin Abdul Rahman, said today that the search has been all but futile: "Unfortunately we have not found anything that appears to be objects from the aircraft, let alone the aircraft."

Ten countries have dispatched ships and aircraft to search for traces of the flight. So far, most analysts believe the plane is most likely to have exploded in the air, according to Reuters

No distress signal was sent from the lost plane, which experts said suggested a sudden catastrophic failure or explosion, but Malaysia's air force chief said radar tracking showed it may have turned back from its scheduled route before it disappeared. A senior source involved in preliminary investigations in Malaysia said the failure to quickly find any debris indicated the plane may have broken up mid-flight, which could disperse wreckage over a very wide area.

Still, any connection between found debris and the missing flight has been dubious at best. One Malaysian official called the disappearance an "unprecedented mystery." 

Security personnel in the Beijing airport. REUTERS//Kim Kyung-Hoo

But nobody is ruling out the possibility of foul play, sparked by the revelation that at least two passengers boarded the flight with stolen passports. During a press conference, Malaysia's Transport Minister, Hishammuddin Hussein responded ambiguously to rumors that a little-known group called the Chinese Martyr Brigade claimed responsibility for the attack in an open letter to a media personality. "Yes, there is sound ground to say it is true, but again, we have said from the beginning that we are not taking anything for granted," he said

In one possibly concrete development, Malaysian officials said that they've identified one of the passengers who boarded the flight illegally. Malaysia's Inspector General of Police said "He's not Malaysian, but I cannot divulge which country he is from yet." With that little to go on, the search continues.