March 19, 2010 -- A Pennsylvania couple on a snorkeling vacation in Aruba believes they inadvertently photographed what may be the skeletal remains of Natalee Holloway, an Alabama high school student who went missing on the Caribbean island five years ago.

The underwater photograph of the sea floor depicts a rough outline the couple believes resemble a human skeleton, according to the Intelligencer Journal/Lancaster New Era, which first published the photo on Thursday.

Patti Muldowney, 62, of Rapho Township, Pa., took the photo while snorkeling off the Caribbean island but "only discovered it after we got the film developed," she told the paper of the body-shaped image in the picture.

Patti and her husband John showed the photograph to local police and forwarded it to FBI, who told them they would investigate.

"It just seems so strange that that girl never showed up, and here we are right off the shoreline, right where she disappeared, and there's a body lying there," said John Muldowney.

"I hate to say I wish it was her, but it would give that family some closure," he said.

Calls to the couple by ABC News were not immediately returned.

Aruban Authorities, however, have yet to receive formal notice from the FBI about the photo, according to Ann Angela, spokeswoman for the Aruban prosecutor's office.

Angela said if the couple can provide "solid information," about the location where the photo was taken, Aruban authorities could send a dive team to investigate. Anything found would be sent to the Dutch Forensic Institute in The Hague.

Angela said it was not uncommon for human remains to be found off the cost and cautioned that even if a body was discovered it may not be Holloway.

Holloway went missing in May 2005 during a high school graduation trip to Aruba. Her disappearance became an international cause célèbre.

Much of the speculation about Holloway's disappearance has focused on Dutch national Joran van Der Sloot, who has twice in recent years seemingly admitted to reporters he knew how and where Holloway died but has never faced charges in her murder.

In February, van Der Sloot told a Dutch television station that Holloway fell to her death from a balcony following a night of drinking and drug use.

"We looked down and saw her lying there. Yes, there was blood. I think she fell on the ground with her head first," van Der Sloot told Dutch television station RTL 5.

"It's a story that in and of itself does fit in terms of timing," Peter Blanken, Aruba's Chief Prosecutor told ABC News in February. "But all the other things that could be investigated, and that means the story about the witnesses […], the house, the height of the balcony, all those types of things don't add up in Joran van der Sloot's statement."

This alleged confession came almost two years after undercover tapes were released by Dutch crime reporter Peter R. de Vries, in which van der Sloot appears to admit he was present when Holloway died and that he helped dump her body in the ocean.