Singaporean diver Rinta Paul Mukkam remained missing yesterday, after a fourth day of searching ended.
Ms Rinta, a 40-year-old associate regional sales manager, failed to surface on Thursday during a diving trip off Komodo Island. She had been part of a group of 16 women who were diving in the area.
Dr Srinesh Balakrishnan, 37, a family friend, said no one has found her, or anything to suggest where she is.
He said posters have been handed out to villages near where Ms Rinta disappeared, offering a reward of US$10,000 (S$13,700) to anyone who finds her.
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About four people have also flown to Indonesia from Singapore to help with the search, including Ms Rinta's brother and brother-in-law.
A fund-raising effort on crowdfunding site GoGetFunding - started by Dr Balakrishnan - has raised slightly over $121,000 of the targeted amount of $250,000.
The money is funding the search-and-rescue efforts.
A second helicopter might be rented today to help with the search. A helicopter costs about US$60,000 per day to rent.
"We want to believe that we're not looking for a body, we're looking for a live person, so we're focusing funds and efforts on (renting a) helicopter," said Dr Balakrishnan.