Compelling new evidence found among the jagged coral of a tiny North Pacific island could be the key to finally unravelling the mystery of exactly what happened to U.S. aviator Amelia Earhart after she disappeared almost 80 years ago.

The corroding pieces of metal, discovered on the Mili atoll in the Marshall Islands, are currently being analysed to find out if they are the wheel well trim and dust cover from Amelia’s Lockheed Electra plane, which disappeared over the Pacific in 1937, while she and her navigator Fred Noonan were attempting to fly around the globe.

The two men behind the find believe that they are in possession of another piece of tantalising evidence that they claim proves she and her companion were captured by the Japanese and died while in their hands.

But by far the most incendiary allegation they make is that the U.S. government knew of the fate of Earhart and Noonan but did nothing to help them and then kept the dark secret for 78 years.

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Mystery: Amelia Earhart and her navigator Fred Noonan had made it most of the way around the world when they disappeared in July 1937 - sparking an enduring hunt to get to the bottom of what happened

Off course: One of the theories is that they landed on the coral shore of a small atoll in the Marshall Islands - a theory Dick Spink (pictured on the island) and Les Kinney hope to prove after finding a piece of metal

Discovery: Two sleuths who have dedicated years to solving the mystery believe the circular piece of metal, left, is a dust cover from the wheel hub of Earhart's plane. It is now with experts who are analysing its authenticity

The fate of Earhart has been the subject of endless worldwide speculation in books, movies, TV specials and has brought numerous researchers into the vast Pacific looking for vital clues.

But the men behind these latest extraordinary claims hope their discoveries will end the speculation once and for all - and within a matter of weeks.

Les Kinney and Dick Spink are convinced a skinny piece of metal and another small, circular piece of metal - which are currently being analysed by the companies which built Earhart's plane - is actually the trim and dust cover from the aircraft's landing gear, which they say broke off when it smashed along the rough coral shore at Mili at about 10am on July 2.

If it is proven to be part of Earhart's Lockheed Electra 10E it means they were more than 850 miles from Howland Island, their next scheduled refuelling stop when they disappeared.

It also puts them 2,000 miles from the spot in the sea where other Earhart sleuths believe the plane, having run out of fuel, crashed on that same morning.

But more than that, if the plane landed on Mili - as Kinney and Spink are convinced it must have - it lends credence to speculation that the doomed adventurers fell into the hands of the Japanese, who just five years later would be engaged in all-out war with the Americans.

Opening doors: If it does prove to be part of the Lockhead Electra 10E (pictured with Earhart in 1937), it will cause people to relook at a number of other theories - including what happened next to the adventurers

Destroyed: A close up of the wheel, which is thought to have been torn up as they landed on the coral

Clues: Spink with the plastic replica of the dust cover that was found on Mili Atoll and a copy of the wheel hub it would have attached to

It has long been rumoured that the 39-year-old pilot and her navigator were captured by Japanese troops who were setting up military bases in the Pacific. Those troops were said to be on board a transport ship heading to the island of Saipan, where Japan had a large military base.

There are those, with Spink and Kinney among them, who claim the Lockheed was put on carts used for transporting ammunition and then loaded on to a barge that was towed to the island of Jaluit. There, it is presumed the plane was lifted onto the ship and then taken to Saipan.

Kinney and Spink, part of a team who travelled to the Mili island last January, found the remains of three of the ammunition cart's metal wheels and axles, while the wooden tops rotted away years ago.

Kinney said: 'The rails were moved and reset until the Japanese reached the lagoon side of the beach where the plane was loaded onto a small barge with the help of 40 locals'.

They did not die as claimed by the government and the Navy when the Electra plunged into the Pacific - they died while in Japanese captivity on the island of Saipan in the Northern Marianas. Amelia Earhart's fourth cousin Wally

Suspected by the Japanese of being spies for the Americans, some claim the pair were held on Saipan until they died despite the lack of physical evidence, with the cause of their deaths the subject of further controversy.

In 2009, Wally Earhart, Amelia’s fourth cousin, said the U.S. government continued to perpetrate a ‘massive cover-up’ about the couple and insisted they had died in Japanese custody.

‘They did not die as claimed by the government and the Navy when the Electra plunged into the Pacific - they died while in Japanese captivity on the island of Saipan in the Northern Marianas,’ said Mr Earhart, who did not reveal his sources.

He said that on Saipan, Noonan was beheaded by the Japanese and Earhart died soon after from dysentery and other ailments.

Kinney and many other Earhart enthusiasts believe her plane was dumped into a giant pit in Saipan along with Japanese aircraft by US marines in the aftermath of World War Two. The pit is under a runway that is still being used. One researcher is trying to get permission to unearth the planes.

Then there was Thomas E. Devine, who served in a postal Army unit who spoke of a letter from the daughter of a Japanese police official who claimed her father was responsible for Amelia’s execution.

Photographs have also emerged over the years claiming to show Amelia in captivity - but these have been found to be fraudulent or to have been taken before she began her flight.

There are also the claims of U.S. troops who landed on Saipan after the war went on to insist they found a safe which, after it was blown open, was found to contain a briefcase filled with Amelia’s flying documents. Another claim, more dubious, tells of the discovery of her documents in a cave on Saipan.

Possibilities: If the duo are right, Earhart and Noonan were more than 850 miles off course. They were meant to land on Howland Island (centre), although others suspect they could have crashed nearer Gardner Island (bottom, far right). It would give credence to the idea they were taken to Japanese base at Saipan (top left)

Route: Earhart was trying to become the first woman to fly around the world - starting in Oakland on May 20

Not impossible: Many said it would be impossible to reach Mili in Earhart's plane, but Spink claims this fuel report proves it would have been possible - lending more credence to their claims

Eyewitnesses: There are also a number of eyewitness accounts, including islanders who said they watched Earhart land to the right of where the research boat (circled) is moored

More hints: These wheels could have been used by the Japanese to take the plane off the island - it would have originally had a wooden platform in the middle, but it has rotten away

But how would all this have been kept quiet for some many years?

Kinney and Spink believe politics, national security and even Japanese loss of face all play their part in the failure for Earhart's fate to be exposed by the U.S. and Japan.

‘At the time, cultural attitudes in Japan placed great emphasis on “saving face”,’ Kinney told MailOnline. ‘The Japanese aversion to being humiliated would not allow an announcement Earhart had been found even if only a few days had elapsed since her discovery on Mili atoll.

‘No less a factor was the rise of Japanese militancy. In the 1930s, the Japanese military considered the United States an enemy and would have quickly concluded, whether it was true or not, that Amelia Earhart had been sent on a spy mission.’

That mission, he said, would likely have been an assessment of whether the Japanese were militarily fortifying the Marshall Islands.

What's more, he believes the U.S. knew within a few weeks that Earhart and Noonan were in the custody of the Japanese but could do nothing.

‘If they had, the Japanese would have known the U.S. had broken their closely-guarded military and diplomatic codes. The U.S. decided Earhart would become expendable.’

But while some will be quick to dismiss this in particular as the wild rantings of a conspiracy theorist, Kinney, a former U.S. Federal law enforcement agent, believes he has one more piece of evidence in his possession which will prove his claim beyond a shadow of a doubt.

Kinney said that after spending hundreds of hours combing national archives in the US, he unearthed one vital document that ‘would be tough for the government to refute.’

He is unwilling to make its contents public yet until his remaining investigations are complete.

Prisoners: Earhart, pictured arriving in Southampton, is said to have been taken from Mili Atoll by the Japanese, who - in some accounts - executed Noonan before she died of dysentery on Saipan

Artifacts: These are other pieces of metal found on Mili. Most have been discounted as not coming from Earhart's plane, but the long piece of metal on the left may be significant

Dedicated: Spink, in his workshop in Washington State, has spent thousands of dollars to prove his theory

Kinney has also relied heavily on an account of the discovery of what is said to have been Amelia’s briefcase on Saipan - a discovery made in July 1944 by U.S. Marine Robert Wallack.

After American troops landed on Saipan, Wallack was part of a team ordered to blow up a Japanese safe.

Inside, he has claimed, he found a briefcase that contained Amelia’s navigational gear, her passport, maps and other personal documents. He gave the briefcase to a high-ranking naval officer on the beach.

‘In my opinion,’ Kinney told MailOnline, ‘the briefcase was sent back to Washington, D.C., some time in late July or August of 1944. It most likely went to the White House and then on to some secure storage facility of the Navy. There is a good chance it later was destroyed.’

It was also in 1944, he says, that two Marine privates, on orders from a watchful Marine Intelligence officer, dug up a grave outside an old Catholic cemetery on Saipan. The skeletal remains of two people were thrown into a canister.

The Japanese would have known the U.S. had broken their closely-guarded military and diplomatic codes. The U.S. decided Earhart would become expendable. Les Kinney

‘When the two privates asked what they were doing, the intelligence officer replied “Have you ever heard of Amelia Earhart?”’

Kinney added that in 1968, four researchers from Cleveland dug up the same grave and unearthed 189 bone fragments. Years later, with the advent of DNA, the researchers tried to retrieve the bones from the archaeological museum where they had been stored - but they were missing.

‘Officials at the museum have no idea what happened to the bones,’ said Kinney.

Kinney, who has been investigating the Earhart mystery for 27 years, dismisses the competing theory that Amelia crashed on Gardner Island, now known as Nikumaroro, while trying to reach her intended destination on Howland Island.

He insisted ‘she didn’t make it - for whatever reason, Earhart missed Howland island from the west and continued in a north-easterly direction.’

Many say the distance to Mili would have been impossible for the Electra to cover.

But Kinney and Spink, a 53-year-old American science teacher who has spent thousands of dollars of his own money investigating the Earhart disappearance, believe it was possible.

They insist that because Earhart had extra fuel tanks on board the plane she had ample fuel to make it - and Kinney has uncovered a Lockheed fuel study which he said proves she could have made it.

And his belief is backed up by contemporary accounts from the islands that they have collected on their visit.

Kinney told MailOnline: ‘After leaving Lae, New Guinea, Earhart must have landed at Mili atoll just after 10am local time. The tidal charts for that time and date indicate the tide was beginning to recede.

‘Two Marshallese eyewitnesses to Earhart’s landing, fishing not far away, said two people left the plane in a small yellow boat.’

They add that numerous people in the Marshall Islands have told them of seeing the two fliers on Mili island before they were captured by the Japanese and taken on board the tramp steamer, the Koshu Maru.

The damaged Electra plane was loaded onto a barge and towed behind the Koshu Maru to two other atolls before mooring at Saipan.

Expendable: Some people also believe the Americans knew Earhart (pictured 1937) had been taken prisoner

Abandoned: Despite being a hero, she was left to her fate as the Japanese believed she was a spy, it's claimed

Spink said he had been told by many people that local Bilimon Amram, who was half-Japanese and working as a medic on Jaluit atoll - one of the atolls the Koshu Maru stopped at to refuel - had claimed he treated Noonan for a leg injury.

‘Everyone told me Bilimon bandaged Fred’s infected leg,’ said Spink, accounts that also convinced him that the two Americans had been picked up on Mili Atoll.

What's more, the men and other members of the Mili expedition found a number of pieces of metal they thought could have been part of a plane - discoveries made more compelling by the fact there were no other planes on the small island and no air battles had been fought overhead or close by.

But one of these pieces, thought to be from an auxiliary power unit, has since been discounted.

So the two men and the rest of the investigating team now pin their hopes on two remaining pieces. The first is the corroded circle they hope may have been the dust shield that fitted over the brake assembly of a GoodYear wheel.

The second is the thin piece of metal they believe is part of the wheel well of the plane.

It is being tested, along with other pieces, by metals giant Alcoa and aviation firm Parker Aerospace who are comparing their chemical elements to those of contemporary aircraft.

The official held belief is that the aircraft is 'on the bottom of the Pacific', 18,000 feet down but close to Howland, said Tom Crouch, senior curator at the U.S. National Air and Space Museum.

In the meantime, Spink still clings to his memory of the extraordinary moment that led to today’s possible breakthrough in the Earhart mystery - a moment during a party with friends in the Marshall Islands.

‘Didn’t Amelia Earhart disappear in this part of the world?’ he asked.

‘Yes,’ a local man answered. ‘She landed on our island and my uncle watched her for two days.’

* At dawn on August 4, 1944, the 2,295-ton Koshu Maru, carrying air base supplies, was hit by four US torpedoes in the Makassar Strait and sank immediately with the loss of 273 passengers, 28 crew members and gunners and 1,239 Javanese labourers.