Amelia Earhart’s disappearance over the central Pacific Ocean 87 years ago remains one of the greatest mysteries in aviation history. Countless theories about her fate have emerged in the decades since, but now a deep-sea exploration team searching for the wreckage of her small plane has provided another potential clue.

Deep Sea Vision, a Charleston, South Carolina-based team, said this week that it had captured a sonar image in the Pacific Ocean that “appears to be Earhart’s Lockheed 10-E Electra” aircraft.

The company, which says it scanned over 5,200 square miles of the ocean floor starting in September, posted sonar images on social media that appear to show a plane-shaped object resting at the bottom of the sea. The 16-member team, which used a state-of-the-art underwater drone during the search, also released video of the expedition.

Tony Romeo, a pilot and former U.S. Air Force intelligence officer, told the Wall Street Journal that he funded the $11 million search by selling off his commercial real estate properties.

“This is maybe the most exciting thing I’ll ever do in my life,” he told the Journal. “I feel like a 10-year-old going on a treasure hunt.”  

Earhart and navigator Fred Noonan disappeared on July 2, 1937, while flying over the Pacific Ocean during Earhart’s attempt to become the first female aviator to circle the globe. They vanished without a trace, spurring the largest and most expensive search and rescue effort by the U.S. Navy and Coast Guard in American history. Earhart and Noonan were declared dead two years later.

Multiple deep-sea searches using high-tech equipment have tried but failed over the years to find Earhart’s plane.

Romeo told the Journal that his team’s underwater “Hugin” submersible captured the sonar image of the aircraft-shaped object about 16,000 feet below the Pacific Ocean’s surface less than 100 miles from Howland Island, where Earhart and Noonan were supposed to stop and refuel before they vanished. 

Romeo’s team didn’t find the image until about three months into the trip, and at that stage it was impractical to turn back, he told the Journal, so they intend to return for a closer look.

Sonar experts told the Journal that only a closer look for details matching Earhart’s Lockheed aircraft would provide definitive proof.

“Until you physically take a look at this, there’s no way to say for sure what that is,” underwater archaeologist Andrew Pietruszka told the newspaper.

There other theories about where Earhart may have vanished. Ric Gillespie, who has researched Earhart’s doomed flight for decades, told CBS News in 2018 that he had proof Earhart crash-landed on Gardner Island — about 350 nautical miles from Howland Island — and that she called for help for nearly a week before her plane was swept out to sea.

Gillespie told CBS News the calls weren’t just heard by the Navy, but also by dozens of people who unexpectedly picked up Earhart’s transmissions on their radios thousands of miles away. Reports of people hearing calls for help were documented in places like Florida, Iowa and Texas. One woman in Canada reported hearing a voice saying “we have taken in water… We can’t hold on much longer.”

Gillespie’s organization, the International Group for Historic Aircraft Recovery, has also claimed that it found forensic evidence, including bones on the island, that were likely Earhart’s.

Still, nearly 90 years later, no wreckage has ever been found, and Romeo thinks his team’s sonar image may finally show the long-lost aircraft.

Romeo, who was joined on the expedition by two of his brothers who are also pilots, told the Journal that their aviation expertise provided a fresh perspective during the search.

“We always felt that a group of pilots were the ones that are going to solve this, and not the mariners,” Romeo told the newspaper.