Holloway disappeared on the last night of a trip to Aruba to celebrate her graduation from high school. Four days later, the Alabama teenager is still missing, despite an extensive search of the Dutch Caribbean island.
"Honestly, at the beginning, we were hopeful the girl would come back," said police Superintendent Jan van der Straaten. "Today, we are more and more thinking about the possibility of a crime."
On the island remarkable for its absence of violent crime, hundreds of residents and tourists posted fliers to help the hunt. FBI agents helped the Dutch military and Aruba police scour outlying scrubland with helicopters and all-terrain vehicles but found no trace of the 18-year-old.
"Everybody has been quite supportive," the teenager's mother, Beth Holloway Twitty, told The Associated Press. "I am not leaving. I am going to have Natalee with me."
Holloway came to Aruba for a five-day excursion with 124 seniors and 40 chaperons from Mountain Brook High School, near Birmingham, Ala. She was last seen around 2 a.m. Monday, Attorney General Caren Janssen said Thursday.
Police discount the possibility she left the island, because they found her passport in her hotel room, van der Straaten said.
Hopes were lifted briefly just before midnight Thursday when a news photographer said he had seen Holloway on the west side of the island. Police rushed to the scene but found an island girl who fit the description but had brown hair, not Holloway's long blond tresses.
Dressed in the same blue-and-green striped, low-cut blouse and denim miniskirt that she wore at the beach earlier in the day, Holloway spent Sunday evening partying at Carlos 'n Charlie's, a popular restaurant and dance spot where tourists and locals meet in the capital, Oranjestad.