"I know we don't have a body, so one can argue that she might still be alive," Taco Stein, an officer in the public prosecutor's office, tells PEOPLE exclusively. "But our position on that is, if that were still the case, she would have come forward and said, 'Here I am, nothing is wrong.' "
Gary Giordano, 50, who initially met Gardener, 35, on Match.com and traveled with her to Aruba on July 31, told police the pair were snorkeling at about 6 p.m. on Aug. 2 off a beach popular among locals but less well-known to tourists.
Courtesy Aruban Public Prosecutor’s Office
Giordano evolved from witness to suspect over the next few days as his story began to veer. "The main gist of the story remained the same," says Stein. "But in asking details, things began to get fishy."
Police arrested Giordano at the airport last Friday as he tried to leave the country, after being told he was not a suspect but should remain available for questioning, says Stein. He has since stopped cooperating, prompting Aruban authorities on Thursday to ask the FBI to help run down leads on Giordano's background in the U.S.
He is being held in a police cell until Monday, when authorities must go before a judge to offer progress in their investigation in order to hold him for another eight days of questioning.
Giordano has not been formally charged.
Reminder of Holloway CaseComparisons between Gardner and the still-unsolved 2005 disappearance of American teen Natalee Holloway in Aruba are tenuous, says Natalee's mom, Beth Holloway. The longtime suspect in the Holloway case, a local resident named Joran van der Sloot, now sits in jail in Peru as a suspect in a murder there last year. But the parallels still sent a shiver.
"It strikes a chord close to home, because that's where Natalee disappeared," says Holloway, who co-founded a missing-persons resource center in her daughter's name that is aiding Gardner's family. "I instantly know this unimaginable nightmare that's ahead of the family in having to navigate the search for a missing loved one in a foreign country."
Gardner's mother Andrea Colson on Thursday released a statement through the Natalee Holloway Resource Center, stating: "We can only pray that she will soon be with us and bring back the joy into our lives. She means the world to us. We are hoping for the very best outcome with the help of the international community that we will reach a favorable outcome."