Another possible clue to the disappearance of a Malaysian jetliner has turned out to be unconnected to the plane.
Malaysian maritime officials had found some oil slicks in the South China Sea, and they sent a sample to a lab to see if the oil came from the missing plane. They say tests showed that the oil was not from an aircraft.
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Earlier, searchers investigated a yellow object that looked like a life raft. It turned out to be trash covered with moss that was floating in the ocean.
Meanwhile, authorities in Thailand have been questioning the owners of a travel agency that sold one-way tickets to two men who are now known to have been traveling on the flight using stolen passports. Interpol says it's trying to determine their identities.
The police agency says it has a database of 40 million stolen or lost travel documents -- but that last year, more than a billion times, travelers boarded planes without their passports being checked against the database.
The plane was on a flight to Beijing when it disappeared over the weekend with 239 people on board.
The head of the organization that monitors the nuclear test ban treaty says he has asked its experts to see if they detected an explosion at high altitude of the missing Malaysian Airlines plane.
Lassina Zerbo, executive director of the Comprehensive Nuclear Test Ban Treaty Organization told a news conference Monday that the CTBTO uses "infrasound" - or infrasonic sensors - to monitor the earth mainly for atmospheric nuclear explosions.
Zerbo said infrasound is the most suitable technology to check if there was an explosion on the missing plane and if there was a monitoring station nearby, "or the explosion is at a level or at an amplitude that it could be detected.
He said he asked the head of the CTBTO's International Data Center to examine the infrasound data.