"We are a very small island with lots of people diving or snorkeling, so it's not unusual for one of us to see an underwater picture and recognize the location," she said.
The area being searched was off the southern part of the Caribbean island, according to one report.
The Muldowneys, of Manheim, Pa., didn't notice anything suspicious during their October vacation or didn't check the photographs until December. Last month, the couple contacted police, and eventually the FBI in Philadelphia.
John Muldowney was confident the image is of human remains. "When I looked at that photo, I said, by darn, that certainly does look like a skeleton," he told CNN's Nancy Grace on Friday night.
Friends agreed the image might show a skull, shoulders, fingers and even deteriorating clothing. "They all agreed that is a corpse," he said.
But others have doubts.
"It could be a skull, it could be a stone, it could be anything," Angela said. "That's what we're trying to figure out."
"I do not believe that these photos represent a body," forensic pathologist Cyril Wecht told ABC News. "I think it's a rock formation that certainly does present upon initial perception a suggestion of a human skeletal remains, but I do not believe that it is."
What appears to be a skull "does not really fit" either a front or rear view, he said.
Dave Holloway, Natalee's father, "is more or less dimishing this," according to Larry Garrison, who has often spoken for the father before.
"I think they've found the same thing other people have found in the past, rock formations."
Richardson told the Birmingham paper, however, that the dive team will continue looking indefinitely.
Patti Muldowney explained to Grace that a boat took them away from shore, where she got into the water with two friends and used a disposable camera "to snap some colorful fish." Her husband remained on the boat, she said.
The 18-year-old Holloway was last seen leaving a bar with Joran van der Sloot, a Dutch national, on the last night of the graduation trip.
Van Der Sloot even confessed twice to media, but the versions contradicted each other, so police, lacking evidence, never filed charges.
Two Aruban brothers were also repeatedly questioned but never charged.
Contact staff writer Peter Mucha at 215-854-4342 or email@example.com.