Police and firefighters have searched an abandoned phosphate mine in Aruba as investigators seek clues in the disappearance of an American tourist and evidence against the man who accompanied her to the Caribbean.

Journalists saw a firefighter leave the mine with a pink shirt and sandals, but it was unclear if they were connected to the investigation. Officials declined to say why the mine at the rocky, cactus-studded southern tip of the island was being searched and the effort was ended late Friday because of darkness. No body or other evidence was seen being taken from the small mine, which is within view of the sea.

Earlier on Friday, Aruban authorities said they believe Robyn Gardner, 35, is no longer alive and are seeking to extend a detention order for her travel companion, Gary V. Giordano, as they seek witnesses who will help them build a case against him, said Taco Stein, solicitor general on the Dutch Caribbean island.

Investigators have few witnesses who saw Gardner and Giordano together in Aruba before he reported her missing, Stein said. Giordano has told police she was apparently pulled away by the ocean current as they snorkeled off the southern tip of the island on Aug. 2.

After so many days, authorities no longer believe the Maryland woman could be alive, so they are holding Giordano on suspicion of involvement in her death. Her remains have not been recovered despite a search of more than four days in the sea and on the coastline in the area where she was reported missing.

"As long as we don't have a body, you can question whether or not she is dead," Stein told The Associated Press in a phone interview. "On the other hand, with all the publicity on the case, if she were still alive she would have made herself known."

Other factors also lead to the conclusion she is dead, Stein told reporters. Police have recovered her passport from her belongings and don't believe she could have left the island by air with a false identity. They have also found no evidence that she left Aruba by boat.

Giordano, a 50-year-old business owner, has denied any wrongdoing through his attorney. He initially helped with the search but Stein said he now declines to answer questions from investigators.

FBI agents searched Giordano's home in Gaithersburg, Maryland, on Friday evening. Agent Phil Celestini said the FBI was executing a federal search warrant and declined to answer questions.

Giordano and Gardner, who is from Frederick, Maryland, arrived in Aruba on July 31 and shared a room at a Marriott hotel. Investigators have surveillance tape of them at a restaurant near Baby Beach, not far from where he says she disappeared while snorkeling. But no witnesses saw them go into the water and police have no knowledge of what else they did on the island, Stein said.

Investigators particularly need details of how the couple behaved together on the island, and whether they seemed close or quarreled. "We have very little information about what they did on the island," Stein said.

Giordano's lawyer, Michael Lopez, has said his client lost track of Gardner while they were snorkeling and is expected to contest the request.

"We feel we have a strong case, but what the judge will think, I don't know," Stein said.

Under Aruban law, which is based on the Dutch legal system, the judge can extend the next detention order for a maximum of eight days at a hearing scheduled for Monday.

After that period, prosecutors could ask a judge to order Giordano held for as long as 60 days while they prepare a case, but that would require more substantial evidence. Charges would be filed at the end of the 60 days if prosecutors take the case to court.

Aruba's system became familiar to many Americans who followed the disappearance in 2005 of Alabama teenager Natalee Holloway. Authorities repeatedly detained individuals suspected of involvement but then later had to release them for lack of evidence. That case was never solved.

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Associated Press writer Ben Fox contributed from San Juan, Puerto Rico.