Oil rig worker thinks he saw Malaysia Airlines MH370 go down in flames

In yet another twist to the mystery of Malaysia Airlines flight MH370, a New Zealand oil rig worker has come forward to say he believes he saw the airplane on fire right around the time it disappeared.

Mr Mike McKay, a worker on the "Songa Mercur" drilling platform in the South China Sea, sent an email to his bosses detailing his version of events.

He said he "observed the plane burning at high altitude...in one piece" about 50-70km from his location, Business Insider reported.

He gave coordinates for the location of the rig, which recently moved from Cuba to the shores of Vietnam. Mr McKay's employer confirms that the letter, posted online by several news outlets on Thursday, is authentic.

Mr McKay, who carries a New Zealand passport, said that he tried to contact Malaysian and Vietnam officials about what he saw "several days ago", adding that he had received no confirmation that they got his message.

"I believe I saw the Malaysian Airlines plane come down. The timing is right," Mr McKay said in the email.

"I observed (the plane?) burning at high altitude.

"While I observed the burning (plane) it appeared to be in ONE piece."

"From when I first saw the burning (plane) until the flames went out (still at high altitude) was 10-15 seconds. There was no lateral movement, so it was either coming toward our location, stationary (falling) or going away from our location," he wrote.

Vietnamese officials confirmed to ABC News that they had received the letter. But they found nothing in the water at the location specified by Mr McKay.

Given the apparent location of the rig, and the original flight path of MH370, it is possible that Mr McKay is correct, the report said. But that would also seem to discount the theory that the plane turned and headed in the complete opposite direction, as some military authorities have claimed.

Meanwhile, officials are expanding their search for the still-missing plane, and the 239 people on board. There are several reports indicating that the plane may have veered off its intended flight path and changed direction before disappearing from radar, but those reports conflict as to where, exactly it went.

At least 10 countries are involved in the Malaysian-led search for the missing jet, which carried passengers from at least 13 different countries, although most of the passengers were Chinese citizens.