While mystery behind missing Malaysia Airlines flight MH370 remains unsolved, more and more conspiracy theories and claims are surfacing. According to the latest update, a British author claims that the plane may have gone down after a "stray bullet" was fired in a possible struggle during a hijack. Meanwhile, scientists questions the investigation and suggests that "pings" were not from the missing Boeing 777. Keep reading to find out more details.

Author and pilot Sylvia Wrigley has come up with a new theory, explaining why MH370 went down, according to Express UK. The aviation expert has penned down a book suggesting what might have happened to missing Malaysia Airlines aircraft.

The author suggests that mystery behind MH370's disappearance involves terrorist hijack. In her book "The Mystery of Malaysia Airlines Flight 370," she explains that terrorists may have hijacked the plane immediately after it took off from Kuala Lumpur. This may have led to protest or struggle by "crew or hero passenger," leading to bullet fire causing hole in the airplane. The bullet may not have had any instant effect, but later it may have caused "decompression" in the jet's cabin. Such an effect would have made everyone onboard unconscious. After flying for several hours on autopilot mode, the plane must have run out of fuel, eventually crashing into the sea.

"A gunshot could have caused a slow decompression undetected by the hijackers and led to them not putting oxygen masks on as the pressure reduced," says Sylvia Wrigley (as quoted by Express UK)

"The sad fact is that we almost certainly have all the information that we are going to get until the aircraft wreckage and black box are located," adds the British author.

The Web site notes that Sylvia, who has written numerous books on aviation, extensively studied MH370 reports posted on the internet by British, Australian, U.S. Chinese and Malay governments.

Meanwhile, scientists are questioning methods of investigators, calling the search for missing Malaysia Airlines flight MH370 a "debacle," reports the Courier Mail.

The Web site notes that the underwater experts and scientists also claim that Aussie PM Tony Abbott's announcement about locating the black box pings were untimely. Scientists say that the PM was "playing politics" and call the announcement "premature."

The anonymous acoustic expert claims that the four pings that were earlier thought to be from MH370 are not from the missing plane. He said these pings most likely came from another "man-made source."

The scientist told that when he saw the "frequency" and "distance between the pings," he knew that the pings were not those coming from the missing airliner.

US deep sea drone Bluefin 21's search was unable to trace anything during its search mission. This supports unnamed underwater scientists' theory.

Missing Malaysia Airlines flight MH370 disappeared on March 8, 2014 with 239 people on board. While there had been numerous conspiracy theories, the investigators have failed to find any traces of the missing Boeing 777.