In an exclusive report, NBCLA has discovered critical documents and never-before-seen photos that not only shed new light on the 74-year-old disappearance of famed aviator Amelia Earhart, but also perhaps deepen the mystery surrounding her fate.

Thee items (photos, embedded below) were shown to NBCLA about two weeks ago inside an airport hangar in Upland, Calif. They include more than a dozen original photos of Earhart, including the negatives; a pair of woman's goggles and a leather cap; plus, what could be considered the Holy Grail for historians: Earhart's "airworthiness certificate" for the plane that she disappeared with in 1937.

The certificate has specific details about Earhart's plane and her flight plan for the historic around-the-world flight in 1937. And until now, it was always assumed to have been with her when she vanished.

"An airworthiness certificate is basically a birth certificate for a plane and pilots are not supposed to fly without one," said retired judge Mike Duggan, who now owns the items. "So, basically just scratch your head and wonder how did I wind up with this?"

Duggan said he inherited the items from a friend who recently passed away. That friend was a mechanic for the now-defunct TallMantz Aviation Company in Orange County.

"I don't know anybody who has seen these things before," said Duggan. "My friend basically pulled them out of the dumpster when they shut down TallMantz Aviation more than 30 years ago."

Paul Mantz, who co-founded TallMantz Aviation was Hollywood's most famous stunt pilot. He was also Earhart's technical advisor and co-pilot on her first around-the-world flight in March 1937.

But that flight was canceled after Earhart had an accident on the departure from Luke Field in Hawaii. Duggan believes that is perhaps when someone took the airworthiness certificate out of the plane.

"The expectation is that Mantz, as her technical advisor, would have safeguarded the paper work for safekeeping so it wouldn't be lost in the dismantling and shipping of her plane back to California for repairs," said Duggan.

"It's not surprising to me that this document was not found in her plane," said Louise Foudray of the Amelia Earhart Birthplace Museum in Atchison, Kan. "We always knew that there was an original document in existence."

Earhart's fate remains one of aviation's greatest unsolved mysteries. Experts over the years have offered different theories about what happened to her.

When she made her second attempt to circumnavigate the globe in May 1937, it was without Mantz. Instead she took navigator Fred Noonan. The official story is that Earhart and Noonan ran out of fuel and crashed at sea while flying over islands in the South Pacific. The U.S. government launched a massive search, but never found Earhart, Noonan or the plane. Earhart was officially declared dead by a California court in early 1939.

Foudray believes the items will only help historians in the quest to find out what happened to Earhart.

"We are just very happy to have anything that will substantiate that there was something else going on other than what had just been reported and for public knowledge," said Foudray. "It's fascinating, it's complicated and we may never have an answer."

As for what will become of this treasure trove of Earhart memorabilia, Duggan plans to donate the items to various museums, including the Amelia Earhart Birthplace Museum in Kansas.

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