ORANJESTAD, Aruba -- Police found nothing but rocks and coral while searching underwater for the remains of missing U.S. teen Natalee Holloway, the Aruba prosecutors' office said Thursday.

Police dove several times on Wednesday and Sunday after an American couple turned over an underwater photo of what they believed might have been her remains, said spokeswoman Ann Angela. The couple were diving while on vacation in Aruba last year.

Divers didn't find any items in the photo, Angela said.

"We looked at it seriously," she said. "It did not prove successful."

The 18-year-old from Mountain Brook, Alabama, disappeared while on vacation in Aruba in 2005 and was last seen leaving a bar with Joran van der Sloot on the final night of a high school graduation trip.

Van der Sloot has been detained several times, but Aruban prosecutors say they lack evidence to charge him.

Police believe the couple from Manheim, Pennsylvania, likely zoomed in on some coral, giving the impression that it might have been a skull and bones, Angela said.

The search was one of many launched to find Holloway.