Story highlights A grainy sonar image has been spotted, an aircraft recovery group says

Historian at Amelia Earhart Birthplace Museum skeptical of anything conclusive showing up

Technology today is advanced enough to locate a plane, a trade association official says

Could search crews be just a few hundred feet from solving a mystery that has riveted millions for 76 years?

That's the question raised by tantalizing evidence published this week by teams trying to find out what happened to famed aviator Amelia Earhart, who vanished along with navigator Fred Noonan during a doomed attempt to fly around the world in 1937.

Yet that evidence has been met with skepticism in some quarters.

Debate about the mystery gained new currency this week after researchers publicized images recorded by search teams scanning the ocean floor nearly a year ago near Nikumaroro Island in the South Pacific.

The International Group for Historic Aircraft Recovery raised the prospect of a big break in the case by publishing an image online. It showed something -- hard for the layman to size up -- on the ocean floor.

The group said, "It's the right size, it's the right shape and it's in the right place."

Photos: Photos: Amelia Earhart: Pioneer of the sky Photos: Photos: Amelia Earhart: Pioneer of the sky Amelia Earhart: Pioneer of the sky – Amelia Earhart laughs before a flight to Northolt, England, in a DH 82 Tiger Moth plane on June 24, 1928. Hide Caption 1 of 8 Photos: Photos: Amelia Earhart: Pioneer of the sky Amelia Earhart: Pioneer of the sky – Earhart poses in front of her plane in the 1930s. Hide Caption 2 of 8 Photos: Photos: Amelia Earhart: Pioneer of the sky Amelia Earhart: Pioneer of the sky – Earhart looks through the cockpit window of her plane. Hide Caption 3 of 8 Photos: Photos: Amelia Earhart: Pioneer of the sky Amelia Earhart: Pioneer of the sky – Earhart stands on the roof of the Hyde Park Hotel in London with Capt. Hilton H Railey on June 20,1928. Hide Caption 4 of 8 Photos: Photos: Amelia Earhart: Pioneer of the sky Amelia Earhart: Pioneer of the sky – A crowd surrounds Earhart, center, upon arrival at Hanworth airfield in London after she crossed the Atlantic Ocean in 1932. Hide Caption 5 of 8 Photos: Photos: Amelia Earhart: Pioneer of the sky Amelia Earhart: Pioneer of the sky – Earhart poses for a photo in Newfoundland, Canada. Hide Caption 6 of 8 Photos: Photos: Amelia Earhart: Pioneer of the sky Amelia Earhart: Pioneer of the sky – Earhart poses with Capt. A. N. White in Northolt, England, on June 20, 1928. Hide Caption 7 of 8 Photos: Photos: Amelia Earhart: Pioneer of the sky Amelia Earhart: Pioneer of the sky – The Lockheed Electra 'Flying Laboratory' piloted by Earhart and Fred Noonan flies over the Golden Gate bridge in Oakland, California, at the start of a planned around-the-world flight on March 17, 1937. The trip had to be abandoned after the plane crashed on takeoff in Hawaii. Hide Caption 8 of 8

Could it really be a piece of Earhart's Lockheed Electra plane?

Louise Foudray, caretaker and historian of the Amelia Earhart Birthplace Museum in Atchison, Kansas, chose her words carefully on Friday afternoon.

"We don't want to shrug off the hard work anyone is doing. We do like the idea that people are still interested," she said. "But we're skeptical."

She said there have been other theories that have emerged. One is that Earhart's plane was forced down by the Japanese around the Marshall Islands. Another is that Earhart secretly returned to the United States and the government gave her a new identity.

There are people out there who buy those theories. But in reality, Foudray said, "no one has yet to come up with anything conclusive."

It wasn't until March that one analyst made a possible connection to Earhart in an online forum for the International Group for Historic Aircraft Recovery.

The group said experts have offered various interpretations. Some think the sonar image could be a man-made object, and others say it could be a geologic feature.

Earhart: The evidence we almost lost

"So did (last summer's) expedition actually succeed in locating the wreckage of the world's most famous missing airplane? Or is this sonar target just a coral rock or ridge?" the organization says on its website. "Of course we're not going to know until we can get back out there, but until then the anomaly is worth close study."

Richard Fredricks, executive director of the American Salvage Association, a trade group, said that "almost anything is possible" these days with advanced technology. And that includes locating a lost airplane.

He cited technology such as side-scan sonar and magnetometers but said finding a lost plane such as the Earhart craft is "more a function of funding than technology." Money is needed to invest in expeditions, he said. The International Group for Historic Aircraft Recovery on its website is asking for contributions to continue its work.

Foudray said she's heard all of the evidence and nothing solid has risen to the surface. And that includes the latest foray into the South Pacific deep.

"We don't expect anything," she said.