"The replacement of that window had to be done in Miami, at a Pan Am facility that was helping Earhart," Gillespie said. "They may have used different materials than Lockheed ... If we can match that rivet pattern in the photo, I don't see how anybody can argue against this any more."

In fact, it seems certain that they will argue. The Earhart bug, when it bites, takes hold like something akin to theology, and supporters of one theory delight in damning others.

"I wouldn't say we're fighting about anything," said Elgen Long, an 86-year-old veteran pilot and author of the 1999 book "Amelia Earhart: The Mystery Solved," widely regarded as the Bible of what's known as the "crashed-and-sank" theory, which goes pretty much the way it sounds. "Everybody is entitled to their own opinion. But everybody should have some facts to back up those opinions, and Mr. Gillespie, well, he doesn't."

Long says Gillespie's metal scrap is obviously from a PBY seaplane (the "flying boat," it was often called) like those flown by the U.S. Navy in the first half of the 29th century and is probably a remnant of some other crash that washed up on Gardner Island, unconnected to Earhart. ("Laughable!" retorts Gillespie.)

Equally scathing is Susan Butler, the Lake Wales writer who authored "East To The Dawn," the definitive biography of Earhart and the basis for the 2009 Hilary Swank film "Amelia." She regards Gillespie as a huckster, constantly devising new Earhart tall tales to raise money for his group.

"He's very creative," she said. "He'll take it to the Nth degree. He can probably even prove it -- for six months, or a year."

Gillespie, accustomed to the criticism ("this is a a field where people have definite views") shrugs it off.

Gillespies' theory is that Earhart landed her plane on a coral reef just off Gardner Island that becomes visible at low tide. For a time, she used the plane's radio to send out distress signals, until rough weather washed the aircraft off the reef into a deep ocean trough below.

More than 100 shortwave radio listeners around the United States -- many of them with enhanced antennas intended to pick up distant signals -- reported hearing distress calls from a woman identifying herself as Earhart in the days after her disappearance. At the time, they were all dismissed as hoaxes or mistaken identities, but Gillespie believes some of them may have been genuine, the product of a signal leakage known as harmonics that was common on early radio transmitters.

Among the most haunting of the reports came from a St. Petersburg teenager named Betty Klenck, who died just last week at the age of 92. In 1937, she was a kid spending her summer afternoons trolling the shortwave radio her father had rigged with a 60-foot antenna, scribbling down in a notebook song lyrics and bits of news she heard.

Three days after the plane went down, Betty stumbled onto a call from someone who identified herself as Earhart. For three hours, the teenager listened, transfixed and jotting notes all the while, as the woman pleaded for help, comforted an apparently injured Noonan, and sometimes cried. "Oh, if they could hear me," she moaned in despair at one point.

Betty's father came home from work about midway through the broadcast and joined her in listening to it. Later he showed her notebook to Coast Guard authorities, who weren't interested, thinking it the fantasy of a bored teenager. Yet the notebook contains intriguing hints of things Betty couldn't possibly have known, and which may support the idea that the woman on the radio was Earhart, calling from Gardner Island.

For instance: Earhart's constant repetition of something that sounded like "New York City." That wouldn't have made much sense. But if the words were "Norwich City," it's another matter: The S.S. Norwich City was a freighter lost at sea in 1929 that washed up on the reef just off Gardner Island. Bits of the wreckage can still be seen there today. They say it looms darkly in the spectral shadows just before dawn.