Legendary aviator Amelia Earhart was attempting to become the first female pilot to fly around the world when her plane disappeared over the Pacific Ocean in 1937.
Last month, the International Group for Historic Aircraft Recovery (TIGHAR) proposed the theory that she landed her plane safely on a remote island and died as a castaway.
Now, scientists say a new discovery shows a striking similarity between the pilot and the partial skeleton of a castaway found on an island of Kiribati in 1940.
A historical photo provided the vital clue.
A strange detail
The bones were uncovered on the island of Nikumaroro, also known as Gardner Island, which is about 640km south of Howland Island.
They were analysed in 1940, but a doctor said they were male, ruling out the possibility they belonged to Earhart.
However, when TIGHAR discovered the files in 1998, scientists said modern techniques proved the bones were "consistent with a female of Earhart's height and ethnic origin".
More recently, anthropologist Richard Jantz was preparing an updated evaluation when he noticed a strange detail: the skeleton's forearms were considerably larger than average.
However, without knowing the dimensions of Earhart's body, Dr Jantz had no way of comparing if her forearms were similarly longer than normal.
The fascinating science
TIGHAR turned to forensic imaging specialist Jeff Glickman for help.
Using a historical photo where both of Earhart's bare arms were visible, he calculated the ratio between the bones in her lower and upper arm.
"Because there is tissue over the skeleton in living people ... the location of each bone end must be estimated," he wrote in a report published last week.
Her clothing also added a layer of difficulty, however, he used the point of her shoulder, the crease of her elbow, and the indent of her wrist as landmarks.
"Given the evidence and my experience in the field of photogrammetry and photo interpretation, I estimate that the radius-to-humerus ratio of Amelia Earhart is 0.76," he wrote.
In other words, the difference between her lower and upper arm was virtually identical to the partial skeleton, unearthed in the South Pacific.
The discovery doesn't conclusively prove the castaway was Amelia Earhart, but it's certainly another step in that direction.