Vietnamese search and rescue teams found what may be part of a door from the doomed Malaysian Airlines plane that vanished early Saturday. The door and a piece of the plane’s tail were seen floating in the ocean about 50 miles south-southwest of Tho Chu island.

Officials released a photo of the door on Sunday. Malaysia Airlines flight MH370 carrying 227 passengers and 12 crew members vanished from the radar about an hour after departing Kuala Lumpur to Beijing.

Investigators believe the plane “disintegrated” in mid air. That theory could explain the lack of a debris field in the sea.

Flight MH370 departed Kuala Lumpur then climbed to a cruising altitude of 35,000 before turning back, investigators say. The plane descended 600 feet before vanishing.

Malaysia’s aviation regulator told the media there were no signals or beacons sent from the plane before it vanished.

The lack of a debris field could indicate a terrorist act, according to an aviation expert.

“If it was a catastrophic event at cruise altitude, the debris field would be hard to detect. In theory, there would be no large sections of the airplane left intact,” said Jonathan Galaviz, an aviation consultant.

“Never have I seen an aircraft losing control and losing all communication,” said Mark Martin of aviation consultancy Martin Consulting.

Two passengers listed on the flight manifest purchased tickets at the same time using passports that were reported stolen in 2012 and 2013. The passport owners -— an Austrian and an Italian — were located and cleared by police.

“It’s pretty easy to pick up a stolen or a counterfeit passport,” a security expert said. But that did not sit well with Home Minister Ahmad Zahid Hamidi, who criticized border officials for letting the two passengers through.

“I am still perturbed. Can’t these immigration officials think? Italian and Austrian but with Asian faces,” he said on Sunday.

The 227 passengers included 20 employees of a global communications firm; 2 American children; an infant, and the niece of Kuching police chief.

A flotilla of ships from numerous countries searched the crash site for signs of wreckage from the doomed Malyasia Airlines plane on Sunday.

Mourners created a detailed sand sculpture in honor of Malaysia Airlines flight MH370 victims.