Holloway is the teenager who vanished on the Caribbean island while on a graduation trip.
After a series of searches, rumors, and false leads, and with their options quickly running out, volunteers have one last place to explore, says Cobiella: a landfill on the southern part of the island.
Natalee's father spent the weekend surrounded by mountains of rotting garbage, searching for any sign of his 18-year-old-daughter.
"If we find the haystack, we can find the needle," insists Dave Holloway. "But where is the haystack?"
Search teams are at the landfill because of accounts from two witnesses, Cobiella says.
One claims he saw three men dump a bag in the middle of the night. Another claims to have seen several men dumping a woman's body at the landfill in late afternoon, two days after Natalee disappeared.
Dave Holloway spoke to the second witness.
"The police have already gone through it. The FBI has already gone through it. But he's insistent that he saw something, so the search team decided they'll hit it one more time."
One more time is the new rallying cry, Cobiella observes. Searchers scoured a northern beach again Sunday, and the latest search of the waterlogged field near the Marriott Hotel has ended, without a single clue.
There's one more place volunteers would like to look, but they can't get in: the home of 17-year-old suspect Joran van der Sloot, the only person still in custody in connection with Natalee's disappearance.
Investigators from Aruba searched the home for hours in mid-June.
Volunteer searcher Tim Miller of EquuSearch, a Texas company, is asking van der Sloot's father to let him look it over one more time.
"We let him know," Miller says, "there could be something back there you don't know, and if you cooperate, it's gonna kind of clear your name."
Beth Holloway Twitty's trip home was the first time she left Aruba since Natalee vanished.
But her family insists it's not giving up.
"As long as we have clues or tips, we'll keep looking," asserts Dave Holloway.