A short, three-minute film that might be the final footage of Amelia Earhart before the aviator disappeared in 1937 has emerged after sitting forgotten on a shelf for decades.

The black-and-white, 16mm film was apparently shot as Earhart posed for her last photo shoot just before the famed aviator attempted to circumnavigate the globe. The cameraman appears to be John Bresnik, the brother of Earhart’s personal photographer, Al Bresnik.

Earhart made two attempts to fly around the world, both in 1937. The first attempt, in March, ended in Hawaii after her plane crashed during takeoff. Earhart began her second attempt in May. She and her navigator, Fred Noonan, disappeared after taking off from New Guinea in July.

Although it appears the film was shot in California before one of the two attempts, it’s not clear whether the footage is from March or May. Even though experts disagree on the exact date of the film, and no one can say for certain that Bresnik was the cameraman, they do agree that the footage is authentic.

According to the Associated Press, Bresnik’s son, also named John, found the film after it sat for half a century in his father’s office. When his father died in 1992, Bresnik took the film to his own California home, where it languished for another two decades.

“It just always sat it in a plain box on a shelf in his office, and on the outside it said, Amelia Earhart, Burbank Airport, 1937,” Bresnik told AP. Bresnik believes his father was behind the camera.

In the film, Earhart walks around her plane on the tarmac and climbs on top of it to pose for photos. Nicole Swinford, who wrote a book to correspond with a publisher’s release of the film, told the AP that she believes Earhart’s playful demeanor in the footage “shows a more feminine side of her.” Swinford believes that the footage was taken in May, just before Earhart began her final flight.

But Richard Gillespie, executive director of the International Group For Historic Aircraft Recovery, disagrees. He told the AP he thinks the footage likely dates from March.

The film was recently published for the first time after Bresnik gave it to the Paragon Agency. The agency is releasing digital copies of the film with Swinford’s book. Eventually, Paragon chief Doug Westfall told the Guardian, the agency plans to turn over the footage to an archive, so it can live in “public hands”