What happened to Natalee Holloway? The answer may be coming this afternoon as Aruban authorities announce results of a forensic investigation of a jaw bone fragment found on Aruba’s Paradise Beach.

The Mountain Brook teen disappeared in 2005 on a graduation trip to Aruba.

Natalee Holloway’s father, Dave, is “cautiously optimistic” the family has an answer to the five year mystery of his daughter’s fate.

Tim Miller, director of Texas EquuSearch, told CBS42’s Kim Rankin he and Dave are encouraged because there aren’t any other young women missing from Aruba, increasing chances the bone fragment is Natalee’s.

Jossy Monsur, editor of the Aruban newspaper El Diario, told CBS42 that prime suspect Joran van der Sloot told police he was with Natalee on that stretch of beach.

Both Monsur and Miller agree with speculation that recent hurricanes stirred up the ocean floor and wave action brought a container with Natalee’s body to the surface and eventually washed up on the beach.

According to CNN, it’s unclear whether Aruban authorities will hold a press conference or simply issue a written statement.