They are at it again. And this time they have a photo.

Since Amelia Earhart, the famous American aviator, and Fred Noonan, her navigator, disappeared somewhere over the Pacific Ocean during a 1937 attempt to circumnavigate the globe, groups of researchers and historians have argued over their fate.

Did they land, or did they crash? Did they drown at sea, or were they marooned? Did their twin-engine Lockheed Electra plunge into the ocean, never to be seen again? Or was it found — and even photographed — on Japanese territory in the years leading up to the United States’ 1941 declaration of war on Japan?

Sunday was the 80th anniversary of the disappearance of Ms. Earhart and Mr. Noonan. So it is perhaps no surprise that National Geographic recently announced that a team of forensic dogs was being dispatched to a remote atoll to search for the duo’s remains. And now History — formerly The History Channel, once known more for its sober documentaries than for reality shows like “Pawn Stars” and “American Pickers” — is debuting a documentary on Sunday about how Ms. Earhart may have ended up in Japanese custody and imprisoned on the island of Saipan.

Various forms of this theory have been tossed around for decades, but a newly discovered photograph is breathing new life into the idea.